Lake Tahoe

Lake Tahoe is a subalpine lake straddling the California–Nevada line at 1,897 m in the Sierra Nevada, the second-deepest lake in the United States at 501 m. Its water clarity has made it a landmark of freshwater diving in the country, and every dive here starts from an elevation few other dive destinations share: altitude-diving procedures apply across the whole lake, not only on its deeper sites, and a computer or table has to be run in altitude mode even for a shallow shore dive.

California State Parks brought the water of Emerald Bay into the park system in 1994, one of the state's first underwater parks, to protect small recreational boats and barges scuttled there once they were no longer wanted. A Historic Barge Dive Site opened to divers in 1998, and in October 2018 the state added three further sites and opened the Emerald Bay Maritime Heritage Trail, with underwater panels and waterproof dive cards describing vessels that range from Ponderosa pine cordwood barges to a 1915 passenger launch.

Away from the bay, Rubicon Wall at D.L. Bliss State Park is a granite cliff that drops far past recreational limits, reached by a long surface swim from Calawee Cove, and Sand Harbor on the Nevada shore is a shallower, calmer site of boulders and sand reached straight off the beach. Both call for a drysuit: even in August the water is near 4°C a few metres down, and there is no hyperbaric chamber at the lake itself, with the nearest in Reno, Sacramento and Chico.