Kauai is the only Hawaiian island with navigable rivers. As the oldest inhabited island in the chain, Kauai has had more time for wind and water erosion to deepen and widen cracks into streams and streams into rivers. Because this is a small island, the rivers aren't long, and there are no rapids, which makes them generally safe for kayakers of all levels, even beginners, except when rivers are flowing fast from heavy rains.

For more advanced paddlers, there aren't many places in the world more beautiful for sea kayaking than Napali Coast. If this is your draw to Kauai, plan your vacation for the summer months, when the seas are at their calmest. Tour and kayak-rental reservations are recommended at least two weeks in advance during peak summer and holiday seasons. In general, tours and rentals are available year-round, Monday through Saturday. Pack a swimsuit, sunscreen, a hat, bug repellent, water shoes (sport sandals, aqua socks, old tennis shoes), and motion sickness medication if you're planning on sea kayaking.

Equipment and Tours

Kayak Kauai. This company pioneered kayaking on Kauai. It offers guided tours on the Wailua River, and sea kayak tours in Hanalei Bay, and along Napali Coast in season. It has consolidated operations, and is now conveniently located in the Wailua Marina. From there, it can launch kayaks right into the Wailua River for its five-hour Secret Falls hike-paddle tour and three-hour paddle to a swimming hole. Kayak Kauai also offers 12-hour escorted summer sea kayak tours and camping trips on Napali Coast. Stand-up paddleboard instruction and sea-kayak whale-watching tours round out its repertoire. The company will shuttle kayakers as needed, and, for rentals, it provides the hauling gear necessary for your rental car. Snorkel gear, body boards, and stand-up paddleboards also can be rented. Wailua Marina, 3-5971 Kuhio Hwy., Wailua (Kauai County), Hawaii, 96746. 808/826–9844; 888/596–3853; www.kayakkauai.com. From $85 (river tours) and $240 (sea tours); kayak rentals from $95 per day.

Kayak Wailua. We can't quite figure out how this family-run business offers pretty much the same Wailua River kayaking tour as everyone else—except for lunch and beverages, which are BYO—for the lowest price, but it does. They say it's because they don't discount and don't offer commissions to activities and concierge desks. Their trips, a 4½-hour kayak, hike, and waterfall swim, are offered six times a day, with the last at 1 pm. With the number of boats going out, large groups can be accommodated. No tours are allowed on Wailua River on Sunday. 4565 Haleilio Rd., behind old Coco Palms hotel, Kapaa, Hawaii, 96746. 808/822–3388; www.kayakwailua.com. $60.

Napali Kayak. A couple of longtime guides ventured out on their own to create this company, which focuses solely on a 17-mile sea-kayaking paddle along Napali Coast from April to October for small groups, or private and honeymoon tours. These guys are highly experienced and still highly enthusiastic about their livelihood—so much so that REI Adventures hires them to run their multiday, multisport tours. If you're an experienced kayaker and want to try camping on your own at Kalalau (you'll need permits), Napali Kayak will provide kayaks outfitted with dry bags, extra paddles, and seat backs, while also offering transportation drop-off and pickup. They also do Napali Coast day tours from Hanalei to Polihale, with a lunch break at Milolii, and rent camping equipment and first-aid kits. 5-5075 Kuhio Hwy., next to Postcards Café, Hanalei, Hawaii, 96714. 808/826–6900; www.napalikayak.com. From $225.

Outfitters Kauai. This well-established tour outfitter operates year-round river-kayak tours on the Huleia and Wailua rivers, as well as sea-kayaking tours along Napali Coast in summer and the South Shore in winter. Outfitters Kauai's specialty, however, is the Kipu Safari. This all-day adventure starts with kayaking up the Huleia River and includes a rope swing over a swimming hole, a wagon ride through a working cattle ranch, a picnic lunch by a private waterfall, hiking, and two "zips" across the rain-forest canopy (strap on a harness, clip into a cable, and zip over a quarter of a mile). They then offer a one-of-a-kind Waterzip Zipline at their mountain stream–fed blue pool. The day ends with a ride on a motorized double-hull canoe. It's a great tour for the family, because no one ever gets bored. 2827-A Poipu Rd., Poipu, Hawaii, 96756. 808/742–9667; 888/742–9887; www.outfitterskauai.com. Kipu Safari $189.

Wailua Kayak & Canoe. This purveyor of kayak rentals is right on the Wailua River, which means no hauling your kayak on top of your car (a definite plus). Guided waterfall tours are also offered. This outfitter promotes itself as "Native Hawaiian owned and operated." No Wailua River tours are offered on Sunday. 162 Wailua Rd., Kapaa, Hawaii, 96746. 808/821–1188; www.wailuariverkayaking.com. $50 for a single, $90 for a double; guided tours from $75.