Sebastião Rodrigues Soromenho (c. 1560–1602) (Sebastián Rodríguez Cermeño in Spanish), was a Portuguese explorer, born in Sesimbra (Portugal), appointed by the king Philip II (Spanish: Felipe II de España; Portuguese: Filipe I de Portugal) to sail along the shores of California, in the years 1595 and 1596, in order to map the American west coast line and define the maritime routes of the Pacific Ocean in the 16th century.