Haringvliet is a closed inlet that forms part of the Rhine and Maas (Meuse) delta via an open connection with the Hollands Diep. In 2014, The Ramsar Site was aligned with the Natura 2000 site, resulting in an increase in its area of 152 hectares. The water level is artificially regulated and varies according to the supply from the Rhine. After the completion of the Haringvliet locks in 1970, the tide largely disappeared and the water turned from brackish to fresh. In an attempt to restore the original brackish condition and enable fish migration, the locks have been partly opened since 2019. The Site regularly supports more than 20,000 wintering waterbirds and nationally endangered and vulnerable species such as avocet, Eurasian spoonbill (Platalea leucorodia) and sandwich tern (Thalasseus sandvicensis). It also plays an important role as spawning, nursery and feeding ground for many fish, and supports nationally endangered molluscs. Human activities include commercial fishing, agriculture, shipping, reed cutting, angling, recreation and tourism. There is a visitors’ centre at Tiengemeten Island. Potential threats to the Site’s ecological character include an increase in tourism activities, urbanization, industrialization, unsustainable water management and eutrophication.