Ideal for those who love fishing, at the entrance of the Guadiana river one can enjoy an excellent view of the neighbouring Spain. In Castro Marim, as the river bed grows larger, the area that is classified as a Natural Reservation is dominated by the fens and by the ancient rice fields. The Guadiana flows along an extension of 803 km and can be navigated in its last 48 km, where its width varies between 100 metres and 500 metres.

Located in the Algarve Leeward area, it covers the Municipalities of Loulé, Faro, Olhão, Tavira and Vila Real de Santo António. The Park is a lagoon system located along 60km, between the sandy peninsulas of do the Ancão and the Manta Rota, being limited at south by a twist of sandy barrier-islands: Barreta, Culatra, Armona, Tavira and Cabanas.

This Natural Park is characterised by the existence of a cordon of dunes and beaches that protects a lagoon area, whose average depth is 2 metres. Part of this is permanently submerged, while another part emerges during low tide. The surface of the Park extends from the Ancão Beach to Manta Rota and includes wide variety of habitats, including barrier islands, salt marshes, sand bars and vasa, dunes, salt marshes, freshwater and brackish ponds, waterways, forests and agricultural areas, which refers to a wide variety of flora and fauna.