Sea lettuce

Sea lettuce

┬ęDorset Wildlife Trust

Sea lettuce

Scientific name: Ulva lactuca
Sea lettuce is unmistakeable - most often a bright green and always translucent, it is found on all UK coasts.

Species information


Length: up to 20cm Frond width: up to 30cm

Conservation status


When to see

January to December


Sea lettuce is a common seaweed, found attached to rocks and other surfaces using a small holdfast or living in rockpools if it has become detatched. The detatched fronds continue to grow and can create large floating colonies. The ruffled fronds are unique - bright green and translucent, being only 2 cells thick. It is this ruffling that gives it the name sea lettuce - as it looks a bit like a lettuce leaf! (The word lactuca in its scientific name means lettuce).

How to identify

Sea lettuce lives up to its name: it looks like green, floppy lettuce leaves which are often tatty in appearance but are quite tough.


Found on all UK coasts.

Did you know?

Sea lettuce is sometimes eaten as 'Green laver' but 'Purple laver' (Porphyra umbilicalis) is much preferred. Both are used to make laver bread - a Welsh speciality - and are also used to complement rice in Japanese and Korean cooking.

How people can help

Seaweeds provide a vital link in the food chain for many of our rarer species. Our seas and coastline are in need of protection if we are to keep our marine wildlife healthy. The Wildlife Trusts are working with fishermen, researchers, 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.