A. Types of Maritime Delimitation Agreements

To date, Southeast Asian states have shown a distinct preference for simple linear settlements, i.e. the drawing of a line, which represents a single-purpose maritime boundary, either of the territorial sea, or the EEZ, or the continental shelf. Of the twenty-nine Delimitation Arrangements listed in Table 1, five are territorial sea delimitations and fourteen are continental shelf boundaries. Arguably, there is one example of a single-purpose EEZ boundary in Southeast Asia, the 1997 Australia-Indonesia EEZ Boundary (which converted the boundary provisionally established in the 1981 Provisional Fisheries Surveillance and Enforcement Arrangement into an EEZ boundary), but this also continued the seabed boundary established in 1972 between Australia and Indonesia. Accordingly, the 1997 Australia-Indonesia EEZ Boundary is more accurately described as a multiple line delimitation (separate boundaries for the EEZ and continental shelf), which will be dealt with below.

States in Southeast Asia have also adopted single multipurpose boundaries, i.e. one boundary which delimits both the EEZ and continental shelf (hereinafter referred to as the “single maritime boundary”), although they are in the minority compared with the single-purpose boundaries above. Of the twenty-nine Delimitation Agreements, five are single maritime boundaries (see Table 1). This is consistent with international state practice as well as judicial preference for a single maritime boundary delimiting both the EEZ and the continental shelf.Footnote ⁵⁰ Judicial and state support for a single maritime boundary appears to be motivated by considerations of simplicity, certainty, and convenience.Footnote ⁵¹ As noted by Judge Oda in Tunisia/Libya:

Despite the perceived advantages of single maritime boundaries, there is no legal impediment to having two separate boundaries. UNCLOS “does not indicate that the boundaries delimiting the continental shelf and the EEZ ought to be combined in a single line”.Footnote ⁵³ Indeed, Southeast Asia is unique in that it is the only region in the world which has adopted two separate boundaries for the EEZ and continental shelf for the same area, departing from judicial preference and state practice. The first example is the 1978 Australia-Papua New Guinea Delimitation (Torres Strait) which establishes two separate boundariesFootnote ⁵⁴ between Australia and Papua New Guinea in the Torres Strait, namely a “seabed jurisdiction line”, which delimits the sovereign rights of each state over the continental shelf,Footnote ⁵⁵ and a fisheries jurisdiction line, which delimits the sovereign rights of each state “for the purpose of exploring and exploiting, conserving and managing fisheries resources other than sedentary species”.Footnote ⁵⁶

The second example of two separate boundaries is in the Timor Sea, where separate boundaries were established between Australia and Indonesia through three consecutive agreements. First, in 1972, Australia and Indonesia established their seabed boundaries in the Timor Sea and Arafura Sea (Arrangement No. 6 in Table 1). Indonesia had argued that equidistance should be the applicable delimitation principle, whereas Australia (arguably bolstered by the 1969 North Sea Continental Shelf cases, which had given support to the idea that the continental shelf was the “natural prolongation” of one's territory) argued that the Timor Trough was the “natural boundary” between Indonesia and Australia. Neither country was able to secure its maximum claim, and a line was drawn between the line of equidistance to the south and the axis of the Timor Trough to the north. The boundary favoured Australia as it gave Australia a greater portion of the seabed. The second agreement in this area came in 1981 in the form of the Provisional Fisheries Surveillance and Enforcement Arrangement, where Australia and Indonesia agreed on a provisional fisheries line which diverged from the seabed boundary and was closer to the equidistance line favoured by Indonesia (see Arrangement No. 19 in Table 1).Footnote ⁵⁷ The third agreement in 1997 (see Arrangement No. 24 in Table 1)Footnote ⁵⁸ converted the provisional fisheries line to an EEZ boundary (based on equidistance) and also extended the 1972 seabed boundary westwards.

B. Baselines in Maritime Delimitation Agreements

A state's maritime zones are drawn from its baselines. Under UNCLOS, a state can draw a normal baseline which follows the low-water line along the coast.Footnote ⁵⁹ However, in localities where the coastline is deeply indented and cut into, or if there is a fringe of islands along the coast in the immediate vicinity of the coast, a state can use straight baselines.Footnote ⁶⁰ States which meet the definition of “archipelagic States” under Article 46 can also draw straight archipelagic baselines.Footnote ⁶¹

Most maritime delimitations take as their starting point the baseline of the territorial sea. Baselines or, more specifically, base points along baselines, are critical in constructing a provisional delimitation line based on equidistance.Footnote ⁶² However, with regard to general state practice, maritime boundary agreements often do not mention the type or co-ordinate of baselines used.Footnote ⁶³ Likewise, it is also often not clear when straight baselines have been used in the construction of a maritime boundary and there are only a few cases in which it is “clear that there is a link between these two sets of lines”.Footnote ⁶⁴ However, in a survey of the world's maritime boundaries carried out in 1993, it was reported that there were some twenty cases in which straight baselines were specifically taken into account, and in some fifty cases they were disregarded either in whole or in part.Footnote ⁶⁵ However, it is not clear how many of these were cases of straight baselines that were adopted contrary to UNCLOS.

In international case-law, the International Court of Justice (ICJ) has found that the issue of determining the baseline for the purpose of measuring the breadth of the continental shelf and the EEZ, and the issue of identifying base points for the drawing of an equidistance line for the purpose of delimiting the continental shelf and the EEZ, are two different issues.Footnote ⁶⁶ The Court is not bound by the base points in baselines determined by the parties.Footnote ⁶⁷ Further, the ICJ has also held that “the method of straight baselines, which is an exception to the normal rules for the determination of baselines … must be applied restrictively”.Footnote ⁶⁸

In contrast to the position taken by the ICJ, a significant number of Southeast Asian states have adopted straight baselines even when they do not meet the required conditions in Article 7 of UNCLOS.Footnote ⁶⁹ Examples of Southeast Asian states which have drawn straight baselines contrary to the requirements in UNCLOS are Cambodia,Footnote ⁷⁰ Malaysia,Footnote ⁷¹ Myanmar,Footnote ⁷² the Philippines,Footnote ⁷³ Thailand,Footnote ⁷⁴ and Vietnam.Footnote ⁷⁵

When concluding Delimitation Agreements, some Southeast Asian states have demonstrated a flexible approach to the use of baselines. There are examples of one party accepting the use of straight baselines by another party even though those straight baselines were not in strict compliance with UNCLOS. A prime example of this is the 1969 Indonesia-Malaysia Continental Shelf Delimitation (Straits of Malacca and the South China Sea). The 1969 Agreement divided the continental shelves of Malaysia and Indonesia into three areas: the Straits of Malacca, the western side of the South China Sea, and the eastern side of the South China Sea. In the Straits of Malacca, a median line was used to divide the continental shelf equally. However, this ostensibly equal division was based on straight baselines being adopted by both Indonesia and Malaysia. Indonesia, of course, argued for the regime of archipelagic waters, which employed straight baselines.Footnote ⁷⁶ Malaysia had not specified its baselines by geographic co-ordinates at the time of signing.Footnote ⁷⁷ However, Malaysia's straight baselines “were apparently intended to put Malaysia on an equal footing in the division of the continental shelf with Indonesia which had previously drawn straight baselines”.Footnote ⁷⁸ Under international law applicable at the time, Malaysia would not qualify as a state entitled to draw straight baselines, which, as mentioned above, is only reserved for states which meet certain geographic conditions.Footnote ⁷⁹ If a strict equidistant line using Malaysia's normal baselines had been used, Indonesia would have gained about 1,000 square nautical miles (sq nm) of continental shelf.Footnote ⁸⁰ Indonesia's acceptance of Malaysia's use of straight baselines was seen as a “gift” from Indonesia to Malaysia for the latter's support of the regime of archipelagic waters during negotiations of the Third UN Convention on the Law of the Sea.Footnote ⁸¹ Indonesia also accepted the questionable use of Malaysia's straight baselines in the 1970 Indonesia-Malaysia Territorial Sea Delimitation (Straits of Malacca). However, it should be noted that the acceptance of Malaysia's straight baselines in these agreements has caused issues in the negotiations of an EEZ boundary with Malaysia in the Straits of Malacca.Footnote ⁸²

There have also been cases where two parties have declared straight baselines in contravention of UNCLOS but have disregarded them for purposes of maritime boundary delimitation, retracting from their extreme claims. For example, while both China and Vietnam proclaimed straight baselines around certain areas of their coast, including straight baselines around China's Hainan Island, they did not do so in the 2000 China-Vietnam Delimitation (Gulf of Tonkin)Footnote ⁸³ (although it has been suggested that a small segment of the agreed boundary appears to have been influenced by straight baselines drawn by China for Hainan Island).Footnote ⁸⁴ Similarly, in the 1997 Thailand-Vietnam Delimitation (Gulf of Thailand), both countries also disregarded their straight baselines for purposes of delimitation of the territorial sea, EEZ, and continental shelf boundary.Footnote ⁸⁵

C. Legal Principles Adopted in Maritime Delimitation Agreements

As mentioned above, both Articles 15 and Articles 74/83 set out the principles relevant for the delimitation of the territorial sea and EEZ/continental shelf respectively. Article 15 endorses equidistance for delimitation of the territorial sea unless special circumstances warrant an adjustment (known as the “equidistance-special circumstances” rule). Articles 74 and 83 merely state that delimitation of the EEZ/continental shelf “should be effected by agreement on the basis of international law, as referred to in Article 38 of the Statute of the International Court of Justice, in order to achieve an equitable solution”. The vagueness of this formulation is attributable to the difficulties in obtaining agreement of the states negotiating UNCLOS on the applicable principles for delimitation.Footnote ⁸⁶ Some states preferred the equidistance principle, taking into account “special circumstances” when necessary, as the main principle of delimitation, whereas others wanted to emphasize equitable principles.Footnote ⁸⁷ Articles 74 and 83 contained language which gave precedence to neither argument. However, over the years, the decisions of international courts and tribunals have attempted to articulate what is meant by “equitable solution” and such jurisprudence is recognized to be relevant to the interpretation of Articles 74 and 83.Footnote ⁸⁸

There are two distinct phases in international jurisprudence. The first phase from 1969 to 1992Footnote ⁸⁹ has been characterized as the “equitable principles-relevant circumstances” phase.Footnote ⁹⁰ Delimitation was to

Under this approach, equitable principles gave no primacy to equidistance as a method of delimitation.Footnote ⁹² Instead, the goal of achievement of equitable results was the most important in delimitation (as opposed to the method of delimitation).Footnote ⁹³

However, this approach was modified in the later cases from 1993 onwards which found that the “equitable principles-relevant circumstances” rule as it had been adopted since 1958 is “closely interrelated”Footnote ⁹⁴ or “very similar”Footnote ⁹⁵ to the “equidistance/special circumstances” method applicable to the delimitation of the territorial sea.Footnote ⁹⁶ This has been described as the “corrective-equity” approachFootnote ⁹⁷ or the “equidistance/relevant circumstances” approach.Footnote ⁹⁸ While the need for an equitable solution is still the defining goal, the courts have now set out a definite methodology in order to achieve such an equitable solution. Initially, this methodology consisted of two steps whereby the courts first drew a provisional equidistance line and will then consider whether there are factors calling for the adjustment of that line in order to achieve an equitable result.Footnote ⁹⁹ Most recently, this has been modified to three steps in the 2009 Black Sea case:Footnote ¹⁰⁰

1. 1. First, the Court will establish a provisional equidistance or median line unless there are compelling reasons that make this unfeasible in a particular case.

2. 2. At the second stage, the Court will consider whether there are factors calling for the adjustment or shifting of the provisional equidistance line in order to achieve an equitable result. During this stage the Court will consider factors such as the configuration of the coasts concerned and the presence of islands.

3. 3. Finally, at the third stage, the Court will verify that the line does not, as it stands, lead to an inequitable result by reason of any marked disproportion between the ratio of the respective coastal lengths and the ratio between the relevant maritime area of each state by reference to the delimitation line. This final check for an equitable outcome entails a confirmation that no great disproportionality of the delimited maritime areas can be evident by comparison to the ratio of coastal lengths.

In this regard, Southeast Asian states have certainly employed international law principles in their negotiations, utilizing the more recognized “equidistance/relevant circumstances” methodology. Fifteen of the Delimitation Agreements in Southeast Asia appear to have adopted equidistance as the applicable method for delimitation.Footnote ¹⁰¹ That said, the relatively high use of equidistance cannot be said to reflect a particular circumstance of the region and merely reflects that equidistance is generally applied as a point of departure in maritime boundary negotiations worldwide.Footnote ¹⁰² Indeed, as mentioned above, the equidistant line has been recognized as having a primary place in delimitation methodology by the ICJ, as reflected by the use of a provisional equidistance line in the first stage of delimitation.

Despite the prevalence of equidistance as a method of delimitation, there are nearly an equal number of Delimitation Agreements in which Southeast Asian states have negotiated variations of equidistance, adjusting the equidistance line to take into account special circumstances. This has not always resulted in an equal division of maritime space.Footnote ¹⁰³ Southeast Asian states have demonstrated a willingness to adopt a flexible approach towards “relevant circumstances”, and on many occasions have not pushed their maximum legal claims in order to get agreement on their maritime boundaries. This will be illustrated with several examples below.

D. Co-operative Arrangements in Delimitation Agreements

Another notable trend in Delimitation Agreements in Southeast Asia is the increasing use of co-operative arrangements in addition to the establishment of a boundary, ranging from loose agreements to co-operate in certain areas to concrete legal arrangements on co-operation with respect to resources.

Approximately half of the Delimitation Agreements contain a provision dealing with “unity of deposits”, i.e. where hydrocarbon resources straddle a boundary. These provisions most frequently simply establish the principle that if there is a common deposit lying across the boundary, there is a duty to negotiate and reach an agreement on the development of straddling resources.Footnote ¹⁴³ However, Delimitation Agreements such as the 1979 Malaysia-Thailand Continental Shelf Delimitation (Gulf of Thailand) establish more specific rules in cases where there is a “unity of deposits”:

There are also examples of more detailed co-operative arrangements on resources which were essential to the conclusion of the boundary. For example, and as mentioned above, the 2000 China-Vietnam Delimitation Agreement (Gulf of Tonkin) was concluded together with the 2000 Agreement on Fishery Co-operation in the Gulf of Tonkin, which established a common fishery zone, a buffer zone for small fishing boats, and a zone for transitional arrangements.Footnote ¹⁴⁵

A more interesting example can be seen in the 2009 Brunei-Malaysia Delimitation, which has yet to be published. From available reports, it appears that on 16 March 2009, Malaysia and Brunei agreed to an Exchange of Letters which established the final delimitation of the territorial sea, continental shelf, and EEZ of both states off Borneo.Footnote ¹⁴⁶ This area had been subject to a long-standing overlapping claim dispute between Brunei and Malaysia, particularly over Blocks L and M, which had been the subject of competing concessions by Malaysia and Brunei. However, along with the Delimitation Agreement, it was also announced that Blocks L and M would be situated on Brunei's continental shelf, but that Malaysia was given “unsuspendable” rights of access for the exploration and exploitation of Blocks L and M in exchange for giving up its claims over these Blocks.Footnote ¹⁴⁷

There are rarely any provisions on co-operation on the maritime environment, although notably, for the first time in Southeast Asia, the 2003 Indonesia-Vietnam Continental Shelf Delimitation (South China Sea) required the two states to consult with each other in order to co-ordinate their policies on the protection of the marine environment.Footnote ¹⁴⁸

E. Factors Driving Delimitation Agreements in Southeast Asia

A. Joint Development of Hydrocarbon Resources

Generally, joint development arrangements are one of the most common types of “provisional arrangements of a practical nature” under Articles 74(3) and 83(3) of UNCLOS. Joint development is usually used as a “generic term”Footnote ¹⁷² and extends from unitization of a single resource straddling an international boundary to joint development of a shared resource where boundary delimitation is shelved because it is not feasible or possible to reach an agreed boundary at the timeFootnote ¹⁷³ (this present paper is concerned with the latter type of joint development arrangement). International courts and tribunals have endorsed joint development agreements as an alternative to maritime delimitation.Footnote ¹⁷⁴ For example, in the North Sea Continental Shelf cases, the ICJ held that joint exploration agreements were “particularly appropriate when it is a question of preserving the unity of a deposit” in areas of overlapping claims.Footnote ¹⁷⁵ In his Dissenting Opinion in the 1982 continental shelf delimitation case between Tunisia and Libya, Judge ad hoc Evensen proposed a system of joint exploration of petroleum resources based on his view that joint development represented an alternative equitable solution to the maritime boundary dispute, which was eventually adopted by the parties.Footnote ¹⁷⁶ In the Eritrea/Yemen arbitration, the Arbitral Tribunal stated that the parties should give every consideration to the shared or joint or unitized exploitation of any such resources.Footnote ¹⁷⁷

In line with state practice and the endorsement of international courts and tribunals, states in Southeast Asia have frequently employed the joint development of hydrocarbon resources as a “provisional arrangement of a practical nature”, pending delimitation of overlapping maritime claims. Out of the ten provisional arrangements referred to in Table 1, eight concern co-operation on hydrocarbon resources.

B. Conflict Management Arrangements

Southeast Asian states have also demonstrated a unique willingness to utilize non-traditional forms of dispute settlement. These include preventive diplomacy, confidence-building measures, and conflict management regimes, as well as Track II diplomacy, all of which are interrelated concepts and which have been used relatively extensively in the South China Sea.Footnote ²⁰⁵ These are not directly targeted at resolving the cause of the dispute, but at preventing existing disputes from escalating, and at fostering an environment of trust and confidence so as to facilitate the resolution of disputes. Such an approach has been described as:

For example, there is the 2002 ASEAN-China Declaration on the Code of Conduct in the South China Sea (see No. 36 in Table 1). While the Declaration is non-binding in that there is no mechanism for enforcement through dispute settlement or otherwise, it would certainly constitute a provisional arrangement as envisaged under Articles 74 and 83. The Declaration includes provisions on information exchange, increased communications and transparency, particularly relating to military matters, confidence-building measures, and measures of self-restraint, as well as co-operative activities.Footnote ²⁰⁷

A further example of conflict management is the 2012 MOU between Indonesia and Malaysia in respect of common guidelines concerning the treatment of fishermen by the maritime law enforcement agencies of the two countries.Footnote ²⁰⁸ This stems from the arrest of fishermen in the overlapping EEZ claims of Malaysia and Indonesia in the Northern Malacca Strait, where they have a continental shelf boundary but no EEZ boundary.Footnote ²⁰⁹ The Parties agreed, inter alia, to co-operate to conduct preventive measures, and instead of arresting the fishermen in disputed waters, both parties agreed that their law enforcement agencies would ask the fishermen to leave the area and return to their home country.Footnote ²¹⁰

A. Trends in Southeast Asian Approaches to Maritime Boundaries

Based on the discussions in Parts III, IV, and V, there are several discernible trends prevalent in Southeast Asian approaches towards maritime boundaries, which have contributed to the high level of maritime boundary arrangements in the region.

First, arguably, Southeast Asian states have a cultural inclination to resolve disputes through consultations and negotiations, coupled with “a dislike of confrontational/adversarial litigation of disputes, particularly third party resolution before a court or tribunal”.Footnote ²²⁵ A paradigm example of this preference is ASEAN, which is a regional organization known for its reliance on consultations and negotiations as a way to settle disputes or conflicts.Footnote ²²⁶ This is commonly referred to as “the ASEAN way”, which has been described as “the principle of seeking agreement and harmony, the principle of sensitivity, politeness, non-confrontation and agreeability, the principle of quiet, private and elitist diplomacy versus public washing of dirty linen, and the principle of being non-Cartesian, non-legalistic”.Footnote ²²⁷ Adversarial third-party dispute settlement processes to resolve disputes, including maritime boundary disputes, are perceived to be the antithesis to such an approach. Possible reasons for this aversion to third-party dispute settlement have been articulated by some scholars, and they include the perception that international law and the jurisprudence of the ICJ reflect a dominant Western philosophy which fails to recognize other cultural traditions,Footnote ²²⁸ a lack of participation by Southeast Asian judges in international courts, and the belief that many disputes in the region “are not amenable to strictly legal resolution because they involve sensitive questions of sovereignty and domestic policies”.Footnote ²²⁹ Regardless of the validity of this assumption, this aversion to binding dispute settlement may explain why Southeast Asian states have been so willing to enter into negotiated agreements rather than risk dispositive binding dispute settlement. Southeast Asian states may feel that given the fluidity of international maritime delimitation law, the outcome of third-party dispute settlement is unclear, that there is too much to lose, and they would rather take their chances with negotiations.

Second, Southeast Asian states have taken an admirably flexible and conciliatory approach towards their Delimitation Agreements, fulfilling their obligation to negotiate in good faith,Footnote ²³⁰ which has made it easier for the relevant parties to come to an agreement. While they have employed international law in these Delimitation Agreements, they have not pushed their maximum claims under international law or strictly insisted on their legal rights. This is shown inter alia by:

1. 1. a readiness to agree to an adjustment of the equidistance line in Delimitation Agreements to take into consideration other circumstances, which may not always result in a division of maritime space in their favour;

2. 2. a willingness to relinquish claims to both territorial and maritime space in order to obtain agreement with the other state. This can be seen in the 1986 Myanmar-India Continental Shelf Delimitation (Andaman Sea, Coco Channel, and in the Bay of Bengal), where Myanmar gave up its claim to Narcondam Islands to India; in the 1982 Cambodia-Vietnam Provisional Arrangement, where Cambodia gave up its claim to Phu Quoc Island; in the 2000 China-Vietnam Delimitation Agreement (Gulf of Tonkin), where Vietnam gave up its claim to historic waters in the Gulf of Tonkin; and in the 2009 Brunei-Malaysia Delimitation (off Borneo), where Malaysia gave up its claim to Blocks L and M in exchange for non-suspendable rights of access to the resources there;

3. 3. the non-insistence on strict legal rights and ability to accept less than maximum legal claims. For example, Indonesia did not object to Malaysia's use of “inferred” baselines,Footnote ²³¹ and Vietnam did not object to China's use of straight baselines around Hainan Island.Footnote ²³² Other examples include the way in which Southeast Asian states and external states have agreed to give reduced effect to some of its offshore features in Delimitation Agreements, even though they were arguably entitled to full maritime zones under Article 121 of UNCLOS.

Third, the relatively high number of Provisional Arrangements entered into by Southeast Asian states in lieu of boundaries reflects a preference for solutions which aim to maintain peace and good relations between parties rather than resolve the underlying cause of the dispute. Because provisional arrangements allow Southeast Asian states to “shelve” contentious issues and focus on co-operative action, they have proved particularly useful in this region. For example, as noted by one scholar, joint development may be “a device of particular interest and appeal to Asian societies” due to their cultural predisposition to “consensus-building as well as in cooperative behaviour governed by rules that emphasize the collectivity rather than the individual”.Footnote ²³³ There is no doubt that the conclusion and implementation of provisional arrangements generally entail a large degree of co-operation and collaboration between states, and require significant political commitment from all parties, as opposed to a dividing line which allocates jurisdiction separately.Footnote ²³⁴

Fourth, one of the major reasons that Southeast Asian states have been willing to enter into some form of maritime boundary arrangements has been because of their need to explore and exploit resources, particularly hydrocarbon resources, in overlapping claim areas. In their quest for economic independence, Southeast Asian states have been well aware of the transformative potential of hydrocarbon resources to developing economies and have been eager to unlock the potential of such resources.

Fifth, there is no doubt that good relations between ASEAN Member States have also played a role in facilitating the conclusion of maritime boundary arrangements. As noted above, the steady march towards regional integration has most certainly provided a environment conducive to the conclusion of maritime boundary arrangements.

B. Contribution Towards the Development of International Law

The fact that states are free to shape maritime delimitation agreements without any recourse to international law principles has tended to undermine the normative contribution that state practice can make to the law of maritime delimitation. It has been observed that “courts have been reluctant to find any evidence of generally acceptable norms in state practice, and they have been unimpressed by statistical surveys demonstrating the preponderance of any particular method”.Footnote ²³⁵ However, as mentioned above, because states will inevitably use international law to frame their negotiations, and because it is assumed that states would not agree to a maritime boundary arrangement which they felt was inequitable, state practice on boundaries still has some relevance to the development of international law principles on delimitation. As noted by Antunes:

Arguably, it is not possible to say with any degree of certainty that Southeast Asian state practice has contributed to the development of the international law of maritime delimitation. The reliance on the “equidistance/relevant circumstances” methodology used in Delimitation Agreements concluded by Southeast Asian states can, at most, be said to reinforce current trends in maritime delimitation law. The reliance of Southeast Asian states on joint development as a solution to their maritime boundary disputes has been widespread, and has also contributed to our understanding on joint development regimes.Footnote ²³⁷ However, it still does not meet the requirements of customary international lawFootnote ²³⁸ in that it is not constant or uniform (Southeast Asian states use a variety of models of joint development) and there is no opinio juris in that there is no evidence that Southeast Asian states believe that joint development (or some other form of provisional arrangement) is binding on them.Footnote ²³⁹

C. Moving Forward on Unresolved Maritime Boundaries

Despite the laudable progress made with maritime boundary arrangements, unresolved boundaries still remain in Southeast Asian waters, and some of them, particularly those in the South China Sea, have the potential to threaten peace and stability in the region.

For example, Cambodia still has to resolve its boundaries with both Vietnam and Thailand in the Gulf of Thailand.Footnote ²⁴⁰ While there are Provisional Arrangements between Cambodia and VietnamFootnote ²⁴¹ and one between Cambodia and ThailandFootnote ²⁴² in the Gulf of Thailand, such arrangements envisage that further negotiations on delimitation will continue regarding the disputed area.

While Indonesia has been particularly active in maritime boundary-making,Footnote ²⁴³ the majority of Indonesia's concluded boundaries are continental shelf boundaries. Indonesia still has to conclude EEZ boundaries with Malaysia in the Northern Malacca Strait, with Vietnam in the South China Sea, with Papua New Guinea, with India in the Andaman Sea, and with Thailand in the Straits of Malacca and in the Andaman Sea. The negotiation of EEZ boundaries with these states may not be a pressing priority for Indonesia, perhaps with the exception of its EEZ boundary with Malaysia in the Northern Malacca Strait. In this area, there exists an overlap in the EEZ claims between the two states which has resulted in several arrests by Indonesian authorities of Malaysian fishermen,Footnote ²⁴⁴ although the recent MOU between these two states may alleviate this issue.

Indonesia also has no boundaries with Malaysia in the Celebes Sea, although the sovereignty dispute between Indonesia and Malaysia over Sipidan and Ligitan has been resolved in favour of Malaysia.Footnote ²⁴⁵ Disputes continue today over access to the hydrocarbon-rich Ambalat Block. Similarly, Indonesia must also negotiate a boundary with Singapore and Malaysia in the eastern Straits of Malacca, where the ICJ decision on sovereignty over Pedra Branca and Middle RocksFootnote ²⁴⁶ has paved the way for delimitation.Footnote ²⁴⁷ Indonesia also has no boundaries at all with Palau, East Timor in the Timor Sea, and the Philippines in the Celebes Sea.Footnote ²⁴⁸

As mentioned above, Malaysia has to resolve maritime boundary disputes with Indonesia in the Celebes Sea, with Singapore in the Straits of Malacca, and with the Philippines in the Celebes Sea, the Sulu Sea, and South China Sea.Footnote ²⁴⁹ The conclusion of boundaries between Malaysia and the Philippines has been complicated by the Philippines’ historical claim to waters within treaty limits established by the colonial powers,Footnote ²⁵⁰ and the Philippines’ dormant claim to Sabah, which is also claimed and administered by Malaysia.Footnote ²⁵¹

Perhaps the most complex and contentious delimitation issues exist in the northwest and the central south part of the South China Sea, surrounding the Paracel Islands and the Spratly Islands, respectively. This area is characterized by sovereignty disputes over islands and other offshore features, and historical claims to waters, as well as a complex geography characterized by a myriad of predominantly small islands, islets, rocks, cays, shoals, and drying reefs.Footnote ²⁵² The Paracel Islands are claimed by China, Taiwan, and Vietnam, whereas the Spratly Islands are claimed in their entirety by China, Taiwan, and Vietnam, and are partly claimed by Brunei, Malaysia, and the Philippines. Delimitation around the Spratly Islands will not be possible until (a) the sovereignty disputes over the offshore features are resolved and (b) claims are made from these offshore features pursuant to Article 121 of UNCLOS (i.e. whether states which have sovereignty over these features will be claiming an EEZ and/or a continental shelf from these features).Footnote ²⁵³

There is no doubt that current Southeast Asian approaches to maritime boundaries, with their emphasis on consensus, compromise, and consultation, are largely responsible for the relatively high number of maritime boundary arrangements in the region. It stands to reason that State Parties to the existing maritime boundary disputes described above should take the same approach that they have adopted in the maritime boundary arrangements already concluded, i.e. an approach driven by the need for consensus, compromise, and consultation, non-insistence on strict legal positions, and a willingness to modify positions or retreat from extreme positions or claims. Apart from the approach taken towards negotiations, the type of boundary arrangement employed by Southeast Asian states to date should also be explored to determine whether such arrangements can be used for existing disputes. For example, Indonesia and Malaysia may wish to explore the feasibility of using two separate boundaries for their EEZ and continental shelf in the Northern Malacca Strait. Similarly, joint development of hydrocarbon resources may be the appropriate solution in the Celebes Sea. Southeast Asian state practice has provided a multitude of examples of effective solutions to boundary disputes and each should be carefully considered by the relevant states.

However, at the same time, there are inherent limitations in relying on negotiations as the only means of resolving maritime boundary disputes. Not only can negotiations be protracted, and in some cases span several decades, there is no guarantee of a final resolution. Further, negotiations are always problematic when each party has differing bargaining power. A state “with a completely unjustified claim may well be able to secure a favourable negotiated settlement by bringing superior power to bear”.Footnote ²⁵⁴

Arguably, a good illustration of the limitations of negotiations is the South China Sea disputes. The first factor militating against any negotiated resolution in the South China Sea is the fact that the underlying dispute is over sovereignty to features in the South China Sea. Sensitive issues relating to sovereignty are rarely resolved by negotiations, and this is especially true in the South China Sea in view of how both the Spratly Islands and the Paracel Islands have become potent symbols of nationalistic rhetoric to the populations of many of the claimants. Any negotiated agreement relating to sovereignty is likely to be perceived negatively by national populations. Second, the fact that there are six parties to the dispute (China, Taiwan, Malaysia, Brunei, the Philippines, and Vietnam) poses a huge challenge to a negotiated resolution. While some of the features are claimed by only China and Vietnam, many of the features are claimed by at least three parties, and in some cases by five parties. If negotiations were to produce a meaningful resolution to the disputes, it would need to take into account the interests and positions of all parties concerned, which may prove to be impossible. Third, agreement on maritime delimitation can only take place when the sovereignty disputes are settled. In lieu of maritime delimitation, the only option for a negotiated settlement would be to set aside the sovereignty disputes and adopt “provisional arrangements of a practical nature”. Again, there are certain obstacles that would need to be overcome. None of the claimants have definitively confirmed what maritime zones they are claiming from the disputed Spratly or Paracel Islands. Because of this, it is infinitely more difficult to determine the ambit of overlapping claim areas that could be subject to “provisional arrangements”. The lack of clarity in the maritime claims, coupled with the lack of trust and confidence between the claimants, presents a major hindrance to the negotiation of provisional arrangements. Fourth, there is unequal bargaining power between China and the rest of the ASEAN claimants. China's economic and growing military might means that it will always be in a stronger position vis-à-vis its ASEAN neighbours, and this of course explains its steadfast insistence on negotiations as being its preferred mechanism for resolving the disputes. Indeed, China has chosen not to participate in the recent arbitral proceedings brought by the Philippines over certain disputes in the South China Sea (not related to either sovereignty or maritime delimitation, although China may think otherwise).

The limitations illustrated underscore the fact that negotiations cannot and should not be the only option for dispute resolution with respect to maritime boundaries. Southeast Asian states should explore other dispute settlement options available to them under international law. One such option is the use of non-binding dispute settlement mechanisms such as mediation,Footnote ²⁵⁵ conciliation,Footnote ²⁵⁶ and inquiry,Footnote ²⁵⁷ which “offer the benefit of a third party opinion with no commitment to accept the result”.Footnote ²⁵⁸ Again, this can greatly aid in a negotiated settlement and incorporates elements which are compatible with the Southeast Asian preference for consultation and consensus without binding them to a decision which may not be in their favour. For example, the “good offices” of the ASEAN Chair, which was Indonesia at the time, was successfully used in the recent rise in tensions between Cambodia and Thailand over Preah Vihear.Footnote ²⁵⁹ Mediation, conciliation, and inquiry, as well as fact-finding over certain issues which need an impartial finding of fact, can be very useful ways to move disputes such as those over the Spratly Islands towards some sort of resolution.

Another option for Southeast Asian states, following the example of Bangladesh and Myanmar (and countless other countries around the world) is to seriously consider utilizing binding dispute settlement mechanisms to resolve both maritime boundary disputes and underlying disputes to such maritime boundary disputes such as disputes over territory. As explained above, there appears to be some reluctance on the part of Southeast Asian states to use binding dispute settlement mechanisms, and this needs to undergo a paradigm shift. Such dispute settlement mechanisms should not be perceived as contrary to “the ASEAN way” of consensus and consultation, but as a peaceful and effective means to settle disputes and ultimately to maintain peace and stability in the region. In order to facilitate this paradigm shift, it is important to understand the advantages of such binding and non-binding dispute settlement mechanisms.

First, because the decisions of courts and tribunals are binding, “litigation is a good way of disposing a troublesome issue when the resolution of a dispute is considered to be more important than the result”.Footnote ²⁶⁰ This is particularly true of maritime boundary disputes which do not involve sensitive questions of sovereignty. Second, even for maritime boundary disputes which do involve sensitive questions of sovereignty, because decisions are given by judges who are perceived as impartial, and which are based on recognized principles, such decisions are considered “rational, orderly and authoritative”.Footnote ²⁶¹ Such decisions may therefore be perceived as fair or neutral by states as well as their national electorates. Third, because it takes decision-making out of the hands of governments, it allows governments to avoid one of the pitfalls of negotiations, namely, the perception of national electorates that governments have given up too much—at the very least, there is an external third party which can be “blamed” for a decision which is not favourable to it.

Fourth, resorting to binding dispute settlement mechanisms can facilitate negotiations towards an agreed settlement. As put by one writer:

This is well illustrated in the Bangladesh-Myanmar dispute. After years of frustrated negotiations, Bangladesh decided to submit the case to binding dispute settlement. After it did so, and after both states had accepted the jurisdiction of ITLOS in 2009, it was reported that they had reached a breakthrough in negotiations and decided to demarcate the boundary using both equity and equidistance principles.Footnote ²⁶³ The pending case before ITLOS is acknowledged to have served as a catalyst for the breakthrough in negotiations.Footnote ²⁶⁴ This shows that negotiations under the “shadow” or “threat” of binding dispute settlement can be much more effective.

There are positive indications that Southeast Asian states will resort to binding dispute settlement mechanisms more frequently. Singapore and Malaysia, as well as Malaysia and Indonesia, have submitted their respective territorial disputes over islands and other offshore features to the ICJ. The Philippines has initiated arbitral proceedings against China, although it is not clear how China's lack of participation will impact the effectiveness of any award rendered by the arbitral tribunal. Additionally, after the adoption of the ASEAN Charter in 2007, ASEAN moved towards being a more “rules based” and legal organization as opposed to the informal structure it had previously been.Footnote ²⁶⁵