Castell de Sant Esteve de Mar, Medieval castle in Palamós, Spain

Castell de Sant Esteve de Mar is a ruined castle on a cliff between La Fosca beach and Cala s'Alguer. Only the bases of some towers and sections of wall remain, including a low rectangular tower cut partly into the rock and a battered wall about 5 metres high. A ruined farmhouse, built against the old fortification, obscures the original entrance.

The castle was first documented in 1063 and came under King Pere II's control in 1277 when he established it as a royal port. This decision led to the founding of the city of Palamós and transformed the site's importance.

The grounds hold remains from Roman times, including pottery and walls built with the opus signinum technique. These finds show the area was inhabited long before the medieval period.

The ruins stand on a cliff between La Fosca beach and Cala s'Alguer, reached by the GR 92 long-distance path from La Fosca. A fence surrounds the remains and prevents entry, so the castle is only visible from outside. The approach crosses rocky ground, requiring sturdy footwear.

Around 1930 the ruined castle was bought by Alexis Mdivani, a Georgian prince, who intended to restore it; his death stopped the work. The site passed into municipal ownership and between 2011 and 2015 the remains were cleared and consolidated under the Romànic Obert programme, backed by the Generalitat and La Caixa.