A plethora of dive operators have set up shop on Hawaii's major islands: Maui, Oahu, the Big Island and Kauai. They do a brisk business whisking divers to the area's signature lava tubes and caverns, ocean pinnacles, drop-offs and reefs. But it's the amazing variety of marine life that makes this rugged volcanic seascape come alive. Because the Hawaiian islands are one of the most geographically isolated spots on Earth, a stunning 30 percent of marine creatures are endemic-found nowhere else on earth. Add in the variety of diving-from beginning to advanced, shore diving to drift-and you begin to understand why this is one of the most visited destinations in the Pacific.

Dive In

Weather: Warm, with cooling trade winds. Temperatures vary little year-round, averaging 68 to 83, with September tending to be the warmest month. The rainy season runs from November to March.

Average Water Temp: Expect mid- to high 70s in winter and spring, low 80s in summer and fall.

Average Visibility: Tends to be excellent, often above 100 feet.

Currency: The U.S. dollar.

Time: Hawaii Standard Time is two hours behind Pacific Standard. Hawaii does not observe daylight saving time.

Direct Dial Code: 808.

Language: English, though some Hawaiian words are commonly used.

Electricity: 110 volts, 60 cycles.

Entry Documents: U.S. travelers need no special documents to enter the state.

Departure Tax: None.

For More Info: Hawaii Visitors and Convention Bureau, www.gohawaii.com.