S. Roque da Meia Praia Fort is located in the parish of Lagos, near the halt of Meia Praia, with prime views from the seafront over the beach and ocean.

Dating from the 17th century and strategically positioned on the coast, this was a complementary defensive fortification for the Algarve in modern age. Partially rebuilt after the earthquake and tsunami of 1755, the Fort continued to play an important role in the defence of the Bay, but was disarmed and dismantled after the Convention of Évoramonte in 1834. Later a Customs Post was installed here, which has since been deactivated.

The fortress is quadrangular with a battery facing the sea and two half bastions that protect the entrance. With blank walls and a stonework frieze three-quarters of their height, it also has a door that faces west, a courtyard with ramp connecting to the upper floor and a small two-storey living quarters.