Raft Spider

Dolomedes fimbriatus


The Raft Spider is a large, chunky spider that lives around the edge of ponds and swamps. Adults sit at the edge of the water, or on floating vegetation, with their front legs resting on the water's surface in order to feel for the vibrations of potential prey. Using the surface tension of the water, they chase out onto the water to catch their prey, which will even include tadpoles or small fish. Raft Spiders will also swim underwater, often diving beneath the surface when threatened.

How to identify

The Raft Spider is a large, rich chocolate-brown spider, with a pale yellow stripe running down each side of the body.

Where to find it

Widespread but scarce.

When to find it

  • May
  • June
  • July
  • August

How can people help

Spiders are beneficial in the garden as they help to keep populations of pests in check. You can encourage spiders into your garden by providing logs, stone piles and less tidy areas for them to live, feed and breed in. In turn, other species will be attracted to the garden as spiders are a food source for many animals, including mammals and birds, providing a vital link in the food chain. To find out more about encouraging wildlife into your garden, visit our Wild About Gardens website: a joint initiative with the RHS, there's plenty of facts and tips to get you started.

Species information

Common name
Raft Spider
Latin name
Dolomedes fimbriatus
Body length: 0.9-2cm
Conservation status