Andradas Fort, Coastal fortress in Guarujá, Brazil.

Andradas Fort is a coastal defense installation in Guarujá, São Paulo state, built largely underground with interconnected chambers. The complex holds storage magazines, engine rooms, a kitchen, and living quarters linked by underground passages.

Construction started in 1938 to defend the port of Santos during World War II. It was the last structure of this type to be built in Brazil.

The fort is named after José Bonifácio, Antônio Carlos and Martim Francisco de Andrada e Silva, political figures of the First Empire and the Regency period. The name was given by Decree No. 5,002 of 27 November 1942, replacing the original Forte do Monduba.

Tours began in 2016, run Tuesday, Thursday, Friday, Saturday and Sunday at 09.00 and 14.00, and must be booked in advance by phone or email. The entrance is on Rua Horácio Barreiro, in the Tombo neighbourhood. The whole Monduba point area is military ground, so beaches such as Moisés (Praia de Fora) and Bueno are closed to access.

The four Krupp guns were last fired on 28 January 1972, when 32 shells were launched in a training exercise at a range of 8 kilometres. The fort was decommissioned that same year, and its battery had been manned since 1942 by the 5th Independent Coastal Artillery Battery.