The raft spider, also known as the Jesus Spider, Dolomedes fimbriatus, is a European spider of the family Pisauridae. The raft spider is one of the two largest spiders in the United Kingdom, and derives its name from its ability to walk on water. Like other Dolomedes spiders it hunts by running on the surface of water, and can submerge altogether to hide from predators. It was described in chapter 5 of the book Svenska Spindlar by the Swedish arachnologist and entomologist Carl Alexander Clerck. It is the type species of its genus.