Who was the leader who led the first groups to San Diegoand built the first forts?

The leader who led the first groups to San Diego and built the first forts was Juan Rodríguez Cabrillo. He was a Portuguese explorer sailing under the Spanish flag and is credited with the European discovery of San Diego Bay in 1542. Cabrillo established the first settlement in the area, which included the construction of forts to secure Spanish claims in California. His expeditions laid the groundwork for future Spanish colonization in the region.