Ullíbarri-Gamboa’s swamp is the biggest one in the Basque Country with its 146 cubic hectometre. It is part of a system of 3 reservoirs and it holds 3 inner beaches whose quality is recognized with the Blue Flag. At the swamp different aquatic sports can be practised, and inside it, we can find a Yacht Club and an island; Zuhatza Island, which holds a complex of hostels in its interior.