Types of British seaweed

Unlike land plants, seaweeds have no branches and leaves, but instead they have fronds. Looking at the shape and colour of the fronds will help you to identify the seaweed. Some fronds have a ridge running down the centre called a mid-rib and some have air-filled bubbles called bladders.

Explore the 12 kinds of seaweed we would like you to find in this survey in the slideshows below.

  • Channelled wrack, Pelvetia canaliculata
    Seaweeds of the upper and middle shore

    How do seaweeds on the upper shore retain their moisture when the tide is out?  And how can you tell how exposed the upper shore is?  Find out more.

  • Dabberlocks, Alaria esculenta
    Seaweeds of the lower shore

    Seaweeds can provide an important habitat for creatures like sea squirts, sea mat and flat periwinkles.  Find out where to look for them on the lower shore.

  • Green seaweed, Ulva species
    Seaweeds in rock pools

    Rock pools are home to some very common seaweeds and also to some more vulnerable species.  Find out how to identify them.

Get involved

Help us find out more about these wonderful organisms by taking part in the Big Seaweed Search.  You don't need to be an expert - just use our downloadable guides.