Fort Access
The Real Forte Príncipe da Beira is located about 25km from the city; arrange transport in advance.





Costa Marques is a remote municipality located in the western part of Rondônia, Brazil, right on the border with Bolivia. The city's identity is deeply tied to the Guaporé River and the monumental Real Forte Príncipe da Beira, a star-shaped Portuguese fortress built in the 1770s to protect the colonial border. Visitors can explore the ruins of the fort, which remains one of the most significant historical sites in the Amazon. Beyond history, the city offers a slow-paced lifestyle where the river is the main attraction for fishing, boating, and observing local flora and fauna. Its position across from the Bolivian town of Buena Vista adds a cross-cultural dimension to the visit.
Costa Marques is a remote municipality located in the western part of Rondônia, Brazil, right on the border with Bolivia. The city's identity is deeply tied to the Guaporé River and the monumental Real Forte Príncipe da Beira, a star-shaped Portuguese fortress built in the 1770s to protect the colonial border. Visitors can explore the ruins of the fort, which remains one of the most significant historical sites in the Amazon. Beyond history, the city offers a slow-paced lifestyle where the river is the main attraction for fishing, boating, and observing local flora and fauna. Its position across from the Bolivian town of Buena Vista adds a cross-cultural dimension to the visit.
The massive 18th-century Real Forte Príncipe da Beira.
Scenic location on the banks of the Guaporé River.
Direct access to the Brazil-Bolivia border.
Opportunities for river fishing and wildlife spotting.
The city is very remote and requires significant travel time from Porto Velho.
Basic amenities and limited luxury accommodation options.
Portuguese is the primary language, with some Spanish understood due to the border.
The Real Forte Príncipe da Beira is located about 25km from the city; arrange transport in advance.
Local boatmen offer trips on the Guaporé River, perfect for seeing the border from the water.
History buffs and travelers seeking off-the-beaten-path Amazonian river experiences.
BRL R$
$30-$60 p/day
Portuguese, Spanish
Download offline maps as mobile data can be unreliable in this remote area.
June-September
The weather is hot with increasing rain; the forest is lush and green.
Heavy rains occur frequently, which can make unpaved roads challenging.
Rainfall decreases, making it a pleasant time for outdoor exploration.
The dry season from June to August is ideal for visiting the fort and river activities.