Marginitermes absitus n. sp., discovered at Cape York and Cape Arnhem in northern Australia, is described from the imago and soldier castes. This termite species is larger than both of the known congeners, M. hubbardi and M. cactiphagus, from the south-western Nearctic and Central America, respectively. The geographical range and isolation of M. absitus represents one of the most disjunct and isolated distributions for any termite genus worldwide. Based on fossil records and tectonic history, the Australian Kalotermitidae, including M. absitus, arrived on the continent by transoceanic rafting during the Tertiary.