A dolphin is an artificially created sea structure that extends above the water level and is not connected to the shore. Dolphins usually consist of a series of piles driven into the seabed or riverbed and then connected above water level to form a platform or anchorage point. Access to a dolphin is usually by boat.

Among other things, they are used as mooring by extending a berth (mooring dolphin) or providing an anchorage (anchoring dolphin).

Dolphins are also used, similarly to boat fenders, to protect existing structures (e.g., buildings) from the possible impact of vessels.

Dolphins find additional uses here:

- to accommodate navigation aids such as lights or daylight beacons

- to display legal information such as speed limits

- Safety information

- Advertising

photo by Niteshift / CC BY (https://creativecommons.org/licenses/by/3.0)

Wismar Port entrance - Schwedenkopf