Plymouth, England, United Kingdom

Plymouth Breakwater

The Plymouth Breakwater is the kilometre-long stone barrier built between 1812 and 1841 to protect Plymouth Sound, and the artificial fort built on its southern end provides one of the most distinctive boat dives in southern England. The base of the breakwater drops to about 18 metres on a mixed bottom of granite blocks, sand and pebbles. The structure has accumulated over a century and a half of marine colonisation: dense plumose anemones, dead man's fingers, jewel anemones in patches, sponges, hydroids and pink coralline algae cover the granite, with kelp forests on the upper margins. Resident species include ballan wrasse, cuckoo wrasse, corkwing wrasse, pollack, bib, conger eels in the gaps between blocks, tompot blennies, lobsters, edible crabs, spider crabs and the occasional cuttlefish in summer. Visibility ranges from 4 to 10 metres and water temperatures vary between 9 and 17 degrees Celsius. Currents are moderate and dives are timed around slack water from Plymouth charter boats. The site is suitable for AOWD divers in drysuits.