Pico dos Marins is a mountain peak in Brazil, between the cities of Piquete and Cruzeiro, state of São Paulo.

The peak stands only about 1 kilometre (0.62 mi) south of the Minas Gerais state border, but it is located entirely in São Paulo territory.

Pico dos Três Estados ("Three-State Peak"), at the border tripoint of São Paulo, Minas Gerais and Rio de Janeiro states, is also much higher at 2,665 metres (8,743 ft).

[2] Pico dos Marins is still often erroneously mentioned as being the highest mountain entirely within the state of São Paulo (i.e., not shared with Minas Gerais or Rio de Janeiro), but at least two Serra Fina mountains are both higher and located wholly within São Paulo: Pico da Cabeça de Touro,[Note 1] southwest of Pico dos Três Estados and the probable true holder of the title, at exactly 2,600 metres (8,500 ft), and Morro do Tartarugão, just southwest of Pedra da Mina, at 2,595 metres (8,514 ft).

Still, Pico dos Marins is the highest point of its section of the range and an important landmark, as its detachment from the main Mantiqueira ridge crest allows it to be easily seen and recognized from a vast extension of the densely populated and highly industrialized Paraíba do Sul river valley to its south.