Forte de São João da Bertioga, Colonial fortress in Parque dos Tupiniquins, Bertioga, Brazil

Forte de São João da Bertioga is a stone fortification with angular sentry boxes facing the water, built on the mainland at the Bertioga bar opposite Santo Amaro Island. Its current form results from reforms, especially in the 18th century and the last in 2001, and since 2014 it has been surrounded by the Parque dos Tupiniquins.

The first permanent fortification on the site was completed in 1560 by order of the King of Portugal, replacing earlier structures: a trench ordered by Martim Afonso de Sousa around 1531 and a palisade built by Diogo de Braga and his sons, destroyed in a Tupinambá attack in 1551. It was called Forte São Tiago until the 18th century, when it received the name São João. The stone bastion with angular watchtowers facing the water was rebuilt and remodelled over the centuries, most recently in 2001.

The fort houses a museum displaying scenes of indigenous daily life, cannons, replicas of Portuguese armor, and historical artifacts from the region. Visitors can observe the everyday objects and tools that shaped life at this location across the centuries.

The fortress is located on Vicente de Carvalho Avenue in central Bertioga and is easily accessible to visitors. Admission is free, and the site welcomes guests throughout the week and weekends, making it a flexible destination for day trips.

The fort was called Forte São Tiago until the 18th century; the dedication to São João da Bertioga replaced it. Its site also held earlier defences: a trench ordered by Martim Afonso de Sousa around 1531 and the palisade of Diogo de Braga and his sons, destroyed in a Tupinambá attack in 1551.