Sea Kayaking -- One of the best ways to explore the fascinating coastline of the islands is by kayak. Aquasports (tel. 800/773-2309 or 805/968-7231; www.islandkayaking.com) and Paddle Sports (tel. 888/254-2094 or 805/899-4925; www.kayaksb.com) both offer guided trips out of Santa Barbara starting around $175 per day per person. Trips can also be arranged through Island Packers or Truth Aquatics and other concessionaires.

Diving -- Half of Channel Islands National Park is underwater. In fact, twice as many visitors visit the waters annually than the number of people who set foot on the islands. Scuba divers come here from all over the globe for the chance to explore stunning kelp forests, shipwrecks, and underwater caves, all with the best visibility in California. Everything from sea snails and urchins to orcas and great white sharks call these waters home.

Truth Aquatics in Santa Barbara (tel. 805/962-1127; www.truthaquatics.com) is the best provider of single- and multiday dive trips to the islands; 1-day trips begin at about $130. Ventura Dive & Sport (tel. 805/650-6500; www.venturadive.com) also offers guided trips, instruction, and rentals.

Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.