Keyhole limpet

Keyhole limpet

Keyhole limpet ©Nigel Phillips

Keyhole limpet

Scientific name: Diodora graeca
Found on rocky shores and seabeds, the Keyhole limpet gets its name from the little hole at the tip of its shell.

Species information


Length: 4cm

Conservation status


When to see

January to December


The Keyhole limpet lives on rocks and under stones on rocky shores and the seabed down to 250m deep. It feeds on sponges, including the Breadcrumb Sponge, using its rasping tongue. Called a Radula, this rasping tongue is the world's strongest biological structure - it has to be to constantly scrape sponges off tough rocks without wearing away. Their shell is oval and conical, with a distinctive hole at the tip that gives them their name.

How to identify

Similar to the Common limpet, but more oval in shape and with a characteristic 'keyhole' shaped opening in the top of the greyish shell, through which it breathes when underwater. The shell is around 4cm length and features characteristic bands of green or brown.


Found on rocky shores around the south and west of the UK. Also found in the Orkney Islands off Northern Scotland.

Did you know?

The hole at the tip of their shell is used for respiration.

How people can help

When rockpooling, be careful to leave everything as you found it - replace any rocks you turn over, put back any crabs or fish and ensure not to scrape anything off its rocky home. If you want to learn more about our rockpool life, Wildlife Trusts around the UK run rockpool safaris and offer Shoresearch training - teaching you to survey your local rocky shore. The data collected is then used to protect our coasts and seas through better management or through the designation of Marine Protected Areas. The Wildlife Trusts are working with sea users, scientists, politicians and local people towards a vision of 'Living Seas', where marine wildlife thrives. Do your bit for our Living Seas by supporting your local Wildlife Trust or checking out our Action Pages.