The Big Island's leeward coast offers some of the best diving in the world; the water is calm, warm, and clear. Want to swim with fast-moving game fish? Try Ulua Cave at the north end of the Kohala Coast. There are nearly two dozen dive operators on the west side of the Big Island, plus a couple in Hilo. They offer everything from scuba-certification courses to guided boat dives.
Kona Diving Company, in the Old Industrial area, 74-5467 Luhia St., Kailua-Kona (www.bottomtimehawaii.com; tel. 808/331-1858). Kona Diving also offers introductory dives in enriched air (Nitrox) for an additional $10 per tank; two-tank dives for $120 to $130.
One of Kona's oldest dive shops, Jack's Diving Locker, 75-5813 Alii Dr. (www.jacksdivinglocker.com; tel. 800/345-4807 or 808/329-7585), has combined another long-time dive company, Kona Coast Divers, into one diving company. Plus, new company (known as Jack's Diving Locker) also has expanded its former 600-square-foot retail store into an 8,000-square-foot dive center with swimming pool (featuring underwater viewing windows), classrooms, full-service rentals, and full-service sports-diving and technical-diving facility. It offers the classic two-tank dive for $125 and a two-tank manta-ray night dive for $145.
Hot-Lava Dives -- Hilo's Nautilus Dive Center, 382 Kamehameha Ave., between Open Market and the Shell gas station (www.nautilusdivehilo.com; tel. 808/935-6939), offers a very unusual opportunity for advanced divers: diving where the lava flows into the ocean. "Sometimes you can feel the pressure from the sound waves as the lava explodes," owner Bill De Rooy says. "Sometimes you have perfect visibility to the color show of your life." As we went to press, Bill was doing these dives when the conditions were right (an unstable collapse of a recent lava field sent 20 acres of lava into the ocean; fortunately, no one was injured). Call to see if Bill is doing the dives; a two-tank dive goes for as much as $500 per person (two-person minimum).
Night Dives with Manta Rays -- A little less risky -- but still something you'll never forget -- is swimming with manta rays on a night dive. These giant, harmless creatures, with wingspans that reach up to 14 feet, glide gracefully through the water to feed on plankton. Jack's Diving Locker, 75-5819 Alii Dr. (www.jacksdivinglocker.com; tel. 800/345-4807 or 808/329-7585), offers its "Manta Ray Madness" for $145 for a two-tank dive and $95 for snorkelers. Everyone from beginners through experts will love this dive. Jack's cannot guarantee that these wild creatures will show up every night, but does boast a more than 90% sightings record.
If Jack's is booked, try Sandwich Isle Divers, 75-5729 Alii Dr., in the back of the Kona Marketplace (www.sandwichisledivers.com; tel. 888/743-3483 or 808/329-9188). It offers two-tank nighttime manta dives for $165 (including equipment), or $140 if you have your own gear.
Weeklong Dives -- If you're looking for an all-diving vacation, you might think about spending a week on the 80-foot Kona Aggressor II (www.aggressor.com; tel. 800/348-2628 or 808/329-8182), a live-aboard dive boat that promises to provide unlimited underwater exploration, including day and night dives, along 85 miles of the Big Island's coastline. You might spot harmless 70-foot whale sharks, plus not-so-harmless tiger and hammerhead sharks, as well as dolphins, whales, monk seals, and sea turtles. Fourteen divers are accommodated in six staterooms. Guided dives are available, but as long as you're certified, just log in with the dive master and you're free to follow the limits of your dive computer. It's $2,735 for 7 days (without gear), double occupancy, which includes excellent accommodations and all meals. Rental gear, from cameras (starting at $100 a week) to dive gear ($120) to computers ($125), is available.
If you come to Hawaii and don't snorkel, you'll miss half the fun. The year-round calm waters along the Kona and Kohala coasts are home to spectacular marine life. Some of the best snorkeling areas on the Kona-Kohala coasts include Hapuna Beach Cove, at the foot of the Hapuna Beach Prince Hotel, a secluded little cove where you can snorkel with schools of yellow tangs, needlefish, and green sea turtles. But if you've never snorkeled in your life, Kahaluu Beach Park is the best place to start. Just wade in and look down at the schools of fish in the bay's black-lava tide pools. Another "hidden" snorkeling spot is off the rocks north of the boat launch ramp at Honaunau Bay. Other great snorkel sites include White Sands Beach, Kekaha Kai State Park, and Hookena, Honaunau, Puako, and Spencer beach parks.
In addition to Snorkel Bob's, you can rent gear from Jack's Diving Locker, Coconut Grove Shopping Center (behind Outback Steak House), Kailua-Kona (www.jacksdivinglocker.com; tel. 808/329-8802).
Snorkeling Cruises to Kealakekua Bay -- Probably the best snorkeling for all levels can be found in Kealakekua Bay. The calm waters of this underwater preserve teem with a wealth of marine life. Coral heads, lava tubes, and underwater caves all provide an excellent habitat for Hawaii's vast array of tropical fish, making mile-wide Kealakekua the Big Island's best accessible spot for snorkeling and diving. Without looking very hard, you can see octopuses, free-swimming moray eels, parrotfish, and goat fish; once in a while, a pod of spinner dolphins streaks across the bay. Kealakekua is reachable only by boat; in addition to Fair Wind and Captain Zodiac, check out Sea Quest Snorkeling and Rafting Adventures (www.seaquesthawaii.com; tel. 808/329-RAFT), which offers unique coastal adventures through sea caves and lava tubes on the Kona Coast, as well as snorkeling plunges into the ocean at the historic Place of Refuge in Honaunau and at the Captain Cook Monument at Kealakekua. The six-passenger, rigid-hull, inflatable rafts can go where larger boats can't. The 4-hour morning tour is $92 for adults and $75 for children, while the 3-hour afternoon tour goes for $72 for adults and $62 for children. During whale season, there's a 3-hour whale-watching cruise for $72 for adults and $62 children. Children under 6 years old, pregnant women, and people with bad backs are not allowed. Discounts for booking online.
If you're not quite ready to make the commitment to scuba but you want more time underwater than snorkeling allows, Big Island Water Sports (www.snubabigisland.com; tel. 808/326-7446) may be the answer. Just like in scuba, the diver wears a regulator and mask; however, the tank floats on the surface on a raft and is connected to the diver's regulator by a hose that allows the diver to go 20 to 25 feet down. You need only 15 minutes of instruction before you're ready to go. Snuba can actually be easier than snorkeling, as the water is calmer beneath the surface. It costs $89 for a 1 1/2-hour dive from the beach, $145 for one dive from a boat, and $170 for two dives from a boat; children must be at least 8 years old.
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.