Beaches of fine white sand, unspoiled nature, huge colonies of seabirds and valuable aquatic reserves are just some of the charms of this Marine-Terrestrial National Park that spreads north-south along the Rias Baixas. It comprises the archipelagos of Cies, Ons, Onza, Cortegada and Salvora and the surrounding waters. This series of islands rise from the Atlantic Ocean to beautify the landscape with the magic of their sea cliffs and the precious mosaic of ecosystems that they are home to.

The islands have an asymmetrical profile with two clearly differentiated sides: the west coast is more rugged where the erosive action of the sea has carved caves in the high cliffs, whereas the eastern side presents a much smoother appearance. It is more sheltered and protected from the wind and open sea and this has allowed the formation of beaches and dune systems.

Cies archipelago, located at the entrance of the Ria de Vigo, is made up of the islands of Faro, Monteagudo and San Martin. It is home to beautiful beaches such as that of Figueiras, the creek at As Cantareira on the island of Monteagudo, or Rodas beach, a spectacular sand isthmus that links Monteagudo and Faro. At 197 metres, Alto de las Cies, in northern Monteagudo is the highest point of the National Park.

Ons archipelago lies at the entrance of the Ria de Pontevedra. It takes its name from the largest isle, on which are to be found traditional island houses with their characteristic horreos or granaries. There is also a lighthouse at the highest point and paradisaical beaches, including the nudist beach at Melide. The closest neighbour is Onza Island which is much smaller and uninhabited, making it the perfect place to practise naturism on its beaches.

Salvora archipelago, located at the entrance of the Ria de Arousa, has been the site of many shipwrecks. Due to the delicacy of its natural environment, the largest of its islands (from which the archipelago takes its name) may not be visited. Right in the middle of the Arousa estuary, and close to the coast, is Cortegada, with its national park, which offers a tremendous density of trees including a truly unique laurel forest.