The Treshnish Isles are a remote chain of islands and skerries situated in south-west Scotland. The islands, numerous skerries, islets and reefs support a breeding colony of grey seals, contributing just under 3% of annual UK pup production.

The archipelago lies, at its closest, 3 km west of Mull (EU-008) and extends along a northeast-southwest axis for a distance of 11 km.

The islands are exposed to the open ocean, uninhabited and have no good landing sites, hence the presence of vibrant wildlife communities.

The islands already have international recognition of their heritage value. They are designated as a Site of Special Scientific Interest (Wildlife and Countryside Act 1981). They are also designated as a Special Protection Area on the Conservation of Wild Birds.