The Otway Basin of southeastern Australia rifted from Antarctica in two distinct stages in the Early Cretaceous. The first stage began around 140 Ma and ended between 110 and 120 Ma and formed an onshore rift; the rift faults typically detached within basement and were oriented between east-west and east-northeast. On the Crayfish Platform, these first-stage rift structures are preserved. The second stage of rifting at about 95 Ma, just prior to sea-floor spreading, had fault trends between east-southeast and southeast. It was less extensive in area, and the zone of highest extension was localized near the junction with oceanic crust. Geohistory and tectonic analyses indicate that both stages of rifting affected the whole southern margin. In the west, however, the first rift began at about 160 Ma, and first-stage trends persisted during the second rift.