As part of an ongoing monitoring study of phytoplankton in coastal lagoons on the east side of the Gulf of California, Pyrodinium bahamense Plate, 1906 var. bahamense was collected in the Topolobampo–Santa Maria–Ohuira coastal lagoon system in the Gulf of California in May 2005. Average concentrations of P. bahamense were 100 cells liter−1. This finding is the first observation of vegetative cells of this tropical species in the Gulf of California and represents its northernmost occurrence to date.