Tasmania’s sea caves and arches form where waves exploit joints, faults and weaker layers in coastal rock. Similar shapes can develop through different geology, so a dramatic opening should not be given one generic origin story.
Tasman Peninsula dolerite
Tasman Arch, the Blowhole and Devils Kitchen occupy a deeply eroded dolerite coast near Eaglehawk Neck. Formed lookouts provide the safe view. Clifftops beyond barriers are unstable and exposed to powerful wind.
Remarkable Cave cuts through sandstone
At the southern end of Port Arthur, steps descend to a viewing platform at Remarkable Cave. Access depends on conditions and the staircase is substantial. The beach beyond can be affected by tide and swell.
Coastal features keep changing
Rockfall, wave energy and weather continue to enlarge caves and remove arches. Never enter an unmarked cave or rock platform based on a photograph. Check park alerts and observe barriers.
Plan these stops through the Tasman Peninsula guide and use the Tessellated Pavement page for another, very different coastal landform.