Based on museum specimens and zooarchaeological material recovered by us, we note the historic presence of a population of sinistrally coiling Partula gibba Férussac, 1821 on the island of Guam. A single extinct population of this species is also known on an island > 150 km to the north. Hence, given the absence of sinistral populations on intervening islands and lack of indigenous cultural transport, we suggest that sinistrality independently evolved at least twice in P. gibba, the only species of Partula Férussac, 1821 outside of Polynesia to regularly display reverse coiling.