São Sebastião was built in the second half of the 15th century when the plague outbreak reached Lagos. The name of the parish came after the saint, São Sebastião (St. Sebastian), which was considered the holy advocate against the plague.

The population that could not live inside the city walls, mostly constituted by fishermen and farmers who lived from selling their goods inside the city the walls, was settled on the outskirts.

Currently, São Sebastião is the most populous parish of Lagos. It includes part of the city of Lagos as well as some surroundings. The city itself comprises the northern part of the old town and the most northeastern areas. Outside the city, comprises the villages of Portelas, Chinicato, Sargaçal, among other smaller areas.

With regards to the most significant heritage, the Church of St. Sebastian is the ex-libris, together with the old the railway station (built in 1924), or the Chapels of São João Batista (St. John the Baptist) and Nossa Senhora dos Aflitos (Our Lady of the Afflicted). Also in the historic centre lies the building of the Municipal Council of Lagos, currently an exhibition site.

Commerce and tourism have a significant weight in the economy of São Sebastião. The diversity and beauty of the countryside and the existence of beautiful beaches it’s allied to the monuments that bear witness to a history of eight centuries.