WSV Den Osse is a sailing and watersports club marina situated on the shore of the Grevelingenmeer, near Brouwershaven in Zeeland.

With around 500 berths and a membership of approximately 580, the harbor accommodates visiting boats as well as permanent berths for vessels roughly 9 to 13 meters in length.

The Grevelingenmeer's tidal-free, clear water makes Den Osse a practical base for family sailing, recreational paddling, and exploring nearby islands and historic waterside towns.

The site is also noted as a dive and snorkel spot, with marine life including crabs, starfish, pipefish, and lobsters around the basalt stonework near the pier. The marina can be reached on VHF channel 31.