Associação Naval do Guadiana is a public-benefit institution founded in 1983 in Vila Real de Santo António, Portugal. Its work is dedicated to nautical activities for sport, recreation and competition, with a focus on the Guadiana River and its surrounding region. The association promotes events that include international canoeing and swimming crossings, sailing competitions and youth participation in the sport. It also coordinates the Baixo Guadiana Nautical Station, working with the municipalities of Vila Real de Santo António, Castro Marim and Alcoutim, as well as Ayamonte in Spain, to support nautical activities across the area.

The association operates a recreational marina near the mouth of the Guadiana, on the Algarve’s eastern edge, and provides information about marina services, navigation rules, waste management and pricing. Its website also features restaurants at the association and marina, including regional cuisine, fresh fish and seafood, with views of the river and neighbouring Spain. Through its sporting events, marina and hospitality services, Associação Naval do Guadiana connects visitors and local communities with the river.