The Pelagatos volcano is situated within the Sierra Chichinautzin Volcanic Field (SCVF), 20 km southeast of Mexico City. Previous radiocarbon (14C) dating has revealed that the age of the Pelagatos volcano ranges from 2.5 ± 0.1 to 14.1 ± 0.2 ka BP (1σ). The analysis of additional cosmogenic radionuclides, such as in situ 10Be, facilitates the confirmation of the geochronology of any geological phenomenon by determining exposure ages in quartz minerals. This study proposes a new chronology for the exposure of the Pelagatos volcano rocks by in situ analysis of 10Be in olivine samples collected from five locations. The average 10Be ages in olivine from Pelagatos rocks range from 3.95 ± 0.97 ka to 5.7 ± 1.4 ka (1σ), with a mean age of 4.6 ± 0.9 ka and 4.9 ± 0.9 ka for flow 1 and flow 2, respectively. These results are consistent with previously reported 14C ages, confirming the reliability of the 10Be exposure ages obtained in this study. The in situ dating of 10Be in olivine minerals presents a viable alternative for elucidating the volcanic history and estimating the timing of the next eruption in this volcanic field.