Australia

The local aborigines in South Australia remember the rising sea level ‘cutting off’ Kangaroo Island (and those on it) about 6000 years ago. Backstairs Passage average depth 40 metres (max, 73 metres).

The separation by flooding of Bass Strait must have been earlier as its average depth is 50 metres (wikipedia) or 60 metres (wikipedia). The rising sea level “forming a marine embayment from 11,800 BP to 8700 BP and the basin rim was completely flooded by about 8000 BP, at which point Bass Strait was formed and Tasmania became a separate island”.