In the 1930s, Brazil decided to modernize both "São Paulo" and "Minas Geraes". "São Paulo"s dilapidated state made this uneconomical; at the time it could sail at a maximum of , less than half its design speed. As a result, while "Minas Geraes" was thoroughly refitted from 1931 to 1938 in the Rio de Janeiro Naval Yard, "São Paulo" was employed as a coast-defense ship, a role in which it remained for the rest of its service life. During the 1932 Constitutionalist Revolution, it acted as the flagship of a naval blockade of Santos. After repairs in 1934 and 1935, the ship returned to lead three naval training exercises. In the same year, accompanied by the Brazilian cruisers and , the Argentine battleships and , six Argentine cruisers, and a group of destroyers, "São Paulo" carried the Brazilian President Getúlio Vargas up the River Plate to Buenos Aires to meet with the presidents of Argentina and Uruguay.