BLUE LAKE, UTAH
Sea Topia Pro-Divers, (801) 776-3483, www.utahdiving.com/BlueLake.htm
A spring-fed pond, Blue Lake squats in the salt flats near the Nevada border. (When you aren't looking down at drifting perch and bass, you might look up to see a B-1 bomber launched from a nearby gunnery range.) Geothermal vents keep Blue Lake's waters in the 70s and 80s year-round, but winter offers special charms. "Dive in 20-degree weather and your hair crystallizes on the way back to your car," says a local.

DIVE CERULEAN, CERULEAN, KENTUCKY
Dive Cerulean, (270) 235-2713, www.divecerulean.com
Sixteen acres of water fill this southwestern Kentucky quarry; better still, it's warm water. "Our quarry's real shallow, 40 feet at the deepest, and it warms up great, unlike a lot of other quarries that are deep and cold," says owner and operator David Westerfield. Eighty-six-degree water, and the chance to happen upon a pink Cadillac or a 50-pound catfish, also make this a great place for snorkelers. If you do like your water cold, then go at the end of December, when Westerfield celebrates his birthday and the New Year with an ice dive and chili fest. "Diving under the ice is really pretty," he says. "Your bubbles are like silver ball bearings bouncing around on the ceiling."

GILBOA QUARRY, OHIO
Gilboa Quarry, (419) 456-3300, www.divegilboa.com
Approximately 60 miles southwest of Toledo, this quarry offers something unique to northwest Ohio. "We have a lot of big fish," says quarry owner and diver Mike Williams. Most notably, 17 paddlefish, strange-looking creatures that appear to be a morph between a swordfish and an overweight shark. Gilboa's paddlefish grow up to seven feet long and weigh as much as 150 pounds. Toothless filter feeders, true, but they have given unsuspecting divers a start. "We've had people tell us they almost swallowed their regulator," says Williams. On shore, another dive rarity: bunkhouses and campsites.