Isla San Pedro Mártir – Midriff Islands & Upper Sea of Cortez

Site Overview

Isla San Pedro Mártir is a remote volcanic island in the upper Sea of Cortez featuring dramatic steep walls descending into deep Gulf waters with dense gorgonian forests, sea lion colonies, and large schools of pelagic fish that thrive in the nutrient-rich currents sweeping past the island. The volcanic geology has created spectacular underwater topography with sheer rock walls dropping from the surface to beyond 40 metres, adorned with massive gorgonian sea fans that extend their polyps into the nutrient-laden current. A permanent California sea lion colony inhabits the island's rocky shores, providing reliable and playful underwater encounters that rank among the best in the Sea of Cortez. Large schools of yellowtail, jacks, and other pelagic species patrol the island's perimeter attracted by the upwelling currents that bring nutrients from the deep Gulf waters. Seasonal hammerhead schools add predator excitement during the warmer months while the island's isolation ensures pristine conditions with minimal human impact. The extreme tidal currents characteristic of the upper Sea of Cortez make this an advanced diving environment requiring careful timing around slack tide periods. Liveaboard expeditions are the primary means of accessing the island, adding genuine expedition atmosphere to the diving experience. The combination of dramatic walls, abundant marine life, and extreme remoteness makes Isla San Pedro Mártir one of the most exciting and challenging dive sites in the Midriff Islands archipelago for experienced divers seeking untouched wilderness diving.