About This Dive Site
West Thumb Geyser Basin offers one of Yellowstone National Park's most unique scuba diving experiences along the western shore of Yellowstone Lake. At 7,733 feet elevation, this 390-foot-deep high-altitude lake features surreal geothermal activity. Divers access the site via shore entry near the basin's boardwalks, finning over contours where cold surface waters, 40 to 50 degrees F in summer, drop to scalding vents inches away. Vertical spires rise from the lakebed, bubbling with geothermal gases that create a champagne-like swim. Visibility ranges 10 to 30 feet, best July through September. Follow NPS regulations: no touching features, obtain dive permits if required, and adhere to Leave No Trace principles by avoiding sediment disturbance.
Safety Considerations
Diving here demands advanced skills due to extreme thermal gradients; sudden shifts from drysuit-cold to boiling can cause thermal shock or burns. High altitude requires PADI or DAN high-altitude dive tables, slowing ascents to 30 feet per minute with safety stops at 10 to 11 feet to prevent decompression sickness. Monitor for nitrogen narcosis at depth. Geothermal booms from pressurized vents pose entanglement or disorientation risks. Bacteria like Naegleria fowleri thrive in warm shallows; avoid head submersion without nose plugs. Wildlife includes grizzlies onshore, so store gear securely. Check NPS alerts for closures from seismic activity.
Essential Gear
Pack a drysuit with heavy undergarments like Pinnacle Merlin for 40-degree F water. Use redundant regulators, 100-cubic-foot steel tanks for high-altitude gas planning, and a dive computer calibrated for 7,733 feet elevation. Include lift bags for shore exits, thermal imaging if available for vent mapping, and signaling devices like SMBs. REI recommends wetsuit hoods and gloves for extra insulation.