Santa Cruz, the Channel Islands' largest at 96 sq miles, claims two mountain ranges and the park's tallest peak, Mt Diablo (2450ft). The western three-quarters is mostly wilderness, managed by the Nature Conservancy and only accessible with a permit (www.nature.org/cruzpermit). The rest, managed by the National Park Service, is ideal for an action-packed day trip or laid-back overnight stay. Boats land at either Prisoners Harbor or Scorpion Anchorage, a short walk from historic Scorpion Ranch.
You can swim, snorkel, dive and kayak here, and there are plenty of hiking options too, starting from Scorpion Anchorage. It’s a 1-mile climb to captivating Cavern Point. Views don’t get much better than from this windy spot. For a longer jaunt, continue 1.5 miles west, along the North Bluff Trail, to Potato Harbor. The 4.5-mile Scorpion Canyon Loop heads uphill to an old oil well and fantastic views, then drops through Scorpion Canyon to the campground. Alternatively, follow Smugglers Rd all the way to the pebble beach at Smugglers Cove, a strenuous 7.5-mile round-trip. From Prisoners Harbor there are several more strenuous trails including the 18-mile round-trip China Pines hike – your efforts will be rewarded by the chance to see the rare Bishop pine.
There's little shade on the island (so avoid midday summer walks), bring plenty of water (available at Scorpion Anchorage only) and make sure you're at the harbor in plenty of time to catch your return boat, otherwise you'll be stuck overnight.