We describe clinical cases caused by Microsporum gypseum in two subadult male California sea lions (Zalophus californianus). Dermatomycosis is uncommonly reported in pinnipeds, including this species. In these cases, skin lesions were multifocal to coalescing, involved all flippers, and were most pronounced on the ventral surfaces of flippers. They were well-demarcated, depigmented, and covered with crusts. The definitive diagnosis was obtained through microscopic examination and fungal culture of skin scrapings. Oral terbinafine and topical enilconazole were used as treatments for 65 days, and complete recovery was subsequently achieved.