In southeast Sabah, the tri-spine horseshoe crab Tachypleus tridentatus was observed for their locomotion activity using data loggers from September to November 2015. A female with acceleration and depth–temperature loggers and five males with acceleration loggers were recaptured between 10 and 49 days after their release. From the record of 194 days, four individuals including the female were active throughout the 24 h cycle, whereas the activity of the remaining two males was consistent with the 12.4 h cycle. Using the 40-day recording, three individuals including the female were primarily active around the new moon and full moon, but they were dormant around the first and third quarter moon days. This result indicated that the female attempted to spawn in the spring tide periods while lingering in the vicinity. Meanwhile, after spawning, the female spent time foraging in shallow water. Through activity recording, all the T. tridentatus in Sabah was active during daytime and nighttime. This result was contrary to T. tridentatus activity cycles in western Japan, where the species was found to be primarily nocturnal. Perhaps, the regional differences in activity cycles for T. tridentatus were related to their population adaptation toward water temperature, depth, and prey-searching periods.