Secret Beach and Skylight Cave are on the eastern shore of Drakes Bay, 2.5 miles from Limantour Beach parking but accessible only at tides of -1 foot or lower. Skylight Cave is a sea cave with a collapsed ceiling that lets daylight in from above — The Keyhole, a connecting rock tunnel, opens at negative tides.
Overview
Skylight Cave sits at the north end of Secret Beach, an intertidal sea cave carved from the coastal bluffs with a ceiling collapse that creates a skylight effect inside. The cave and the narrow Keyhole passage to the adjacent cove are passable only at significant negative tides. Both are within the Phillip Burton Wilderness.
What to Expect
The approach from Limantour Beach follows the shoreline and coastal trail. Route distance varies by how you access the beach. The cave requires scrambling over wet rocks. At anything above a -1 foot tide, the cave approaches are underwater — visiting at higher tide is genuinely dangerous. Steep scrambles are required to access the cave from the beach.
Tips & Logistics
Check tide tables before going — only negative tides allow safe access. Avoid high surf advisories. The Limantour Beach parking area is about 20 minutes from Bear Valley. Dogs are not allowed. No permit required. Most reliably accessible October through March when low tides occur during daylight hours.