[1][2] It is about 28 hectares (69 acres) in extent and is 0.65 miles at its longest by 0.33 miles at its widest The coastline is largely cliff-lined and rocky however slopes down to the northernmost part of the island at which point it is possible to land by small boat or kayak.

Tarner Island is dotted with small sea caves around the perimeter, many large enough to kayak into, and there is a natural arch to the north.

The west of the island is dominated by cliffs and a large leaning boulder, known as 'Fingal's Limpet Hammer'.

("A huge block of trap, which has slipped from the face of a cliff in one of the islands of Loch Bracadale in Skye, is called ' Ord-bàirnich Fhinn,' Fingal's limpet-hammer.

"[3] Tarner Island is 0.5 miles from mainland Skye at its nearest point and there are several skerries including Sgeir Mhòr and Sgeir Bheag that lie just offshore to the north east between the island and Colbost Head.