Isla San José is an island in the Gulf of California, off the east coast of the Baja California peninsula. Located some 60 km north of the city of La Paz, it belongs politically to the Mexican state of Baja California Sur and is part of the Municipality of La Paz. Its surface area is 182.962 km² (70.642 sq mi), the sixth-largest island in Mexico.
It is the type locality for the Yellow-footed Gull.