Where else can you snorkel and dive in starfish-rich kelp forests within spitting distance of both Santa Barbara and Los Angeles? Your starting block: Ventura, home to Island Packers' ferry launch. Your destination: Santa Cruz, the largest and wildest of the islands—76 percent is Nature Conservancy–owned. Bring snorkeling or dive gear (or rent at Ventura's Peace Dive Boat), set up camp at Scorpion Landing, on the island's eastern tip, pull on your fins, and drift to nearby Little Scorpion Cove, a complex of kelp forests plied by sea lions. Next morning: Repeat the snorkeling part.

EXPENSE REPORT Ferry (islandpackers.com): $128 round-trip for two. Campsite (reserve at recreation.gov): $30 for two nights. Camp food (bagels, avocado, cheese): $15. Two-day gear rental for two (805-650-3483): $160 (snorkel) or $300 (scuba). Mahi-mahi dinner at Ventura's Spinnaker Seafood Broiler (805-658-6200): $45. A night at Ventura's Bella Maggiore (800-523-8479): $110. Total: $488 (with snorkel)