During 1998 and 1999, fixed structural timbers above mean sea level and driftwood along the coastline of England (South from Lancaster and Middlesborough) and Wales were surveyed for invertebrate colonisers. The cossonine Pselactus spadix was the most common coloniser, present in 63% of timbers surveyed, including hardwoods and softwoods, with moisture contents ranging from 17% to 256%, in the mid intertidal to splash zones. Microscopic examination of wood adjacent to P. spadix tunnels showed that soft rot decay was normally present, although there was no evidence of decay in 15% of the Pselactus colonised timbers. Other Coleoptera colonising timbers above mean sea level included Nacerdes melanura (13%), tunnelling softwoods in the high intertidal to splash zones and anobiids (8%), tunnelling hardwoods and softwoods above the mid intertidal zone. Limnoria spp. (Isopoda) were present in 7% of the timbers surveyed, colonising hardwoods and softwoods below the mid intertidal zone. Driftwood was colonised by marine Mollusca and Crustacea, and terrestrial Arthropoda (Coleoptera and Myriapoda). The presence of terrestrial species in 61% of the driftwood samples suggests this may be a common dispersal mechanism.