Marking techniques are essential for studying bat ecology and informing conservation efforts, yet many existing methods present challenges related to size, tag detectability, and long-term retention. p-Chips, ultra-miniaturized transponders detectable via red laser light, offer a promising alternative to traditional banding or passive integrated transponder (PIT) tags. While their use has been successfully demonstrated in captive bats, their effectiveness in free-ranging populations remains largely untested. We individually tagged 31 species of bats with p-Chips during a 3-year study in the Peruvian Amazon. We documented 88 recaptures, with all p-Chips remaining functional over both short-term (within the same sampling season, ≤ 40 days) and long-term (across sampling seasons, more than 170 to more than 850 days) periods. Notably, no adverse effects such as scarring or tissue damage were observed. Red light-emitting diode (LED) illumination facilitated rapid visual detection of tags, reducing handling time. These findings support the use of p-Chips as a viable, detectable, minimally invasive, and cost-effective alternative to PIT tags, particularly for small-bodied species. We recommend further research to optimize p-Chip technology for broader application in wildlife tracking and conservation.