The Ria de Alvor lagoon is a protected nature reserve on the southern coast of Portugal, between Alvor and Lagos. It consists of a vast lagoon with sandbanks, dunes, salt marshes, and tidal creeks. This ecosystem is rich in biodiversity and especially popular with birdwatchers for its many migratory birds. The area is a Natura 2000 site and is important for the Algarve's ecological balance.