T'Lani III was the third planet of the T'Lani system. This world was formerly inhabited by the T'Lani species. The entire population of the planet was wiped out by Harvesters, deployed during the war against the Kellerun that ended in 2370.
Miles O'Brien and Julian Bashir hid in an abandoned bunker on T'Lani III after the T'Lani and Kellerun authorities attempted to eliminate them and their knowledge of the Harvesters. (DS9: "Armageddon Game")