The Ostioneros were one of the four original founding members of the
Mexican Pacific Coast League, a winter league circuit that operated in
Mexico in the seasons from 1945–46 through 1957–58. The team won pennant titles in the 1947–48 and 1950–51 seasons,
managed by Juan Guerrero and Luis Montes de Oca, respectively. In 1950–51, Ostioneros shared the league championship with the Tacuarineros de Culiacán. Before the 1958–59 season, the circuit was renamed Sonora Winter League and lasted through the 1991–92 season. and 1967–68 with
Ronaldo Camacho, to won seven league titles in both stints. The Ostioneros name has since been used by other sport clubs based in Guaymas. ==Championships==