Diving in a mountain lake or reservoir is a real thing, but it follows different rules than sea-level diving. At altitude the lower surface pressure changes how nitrogen behaves, so your usual dive tables and habits need adjusting. Understanding altitude diving keeps you safe when the water sits far above the ocean.
What counts as altitude
In diving, altitude generally means any dive site above 300 meters (about 1000 feet) of elevation. Many popular sites in the Andes, the Alps and high reservoirs fall well into this category.
The higher you go, the thinner the air above the water, and the greater the difference between the pressure at depth and the pressure when you surface.
Why nitrogen behaves differently
At altitude the surface pressure is lower than at sea level, so when you ascend you experience a proportionally bigger pressure drop. That larger change means nitrogen comes out of solution more readily, raising decompression risk if you use ordinary sea-level limits.
To stay safe, divers use altitude-adjusted tables or a dive computer set to altitude mode, which automatically applies more conservative no-decompression limits.
Extra precautions
Altitude diving asks for a few added habits:
- Take specialized altitude diver training before attempting it
- Let your body acclimatize to the elevation before diving
- Use an altitude-capable dive computer or proper tables
- Ascend even more slowly and make conservative safety stops
Cold water, thinner air and remoteness at altitude also mean planning and fitness matter more than usual.
Do not forget the drive home
Altitude rules cut both ways. If you dive at sea level and then drive up into the mountains, that ascent counts just like flying, and you must wait long enough to off-gas before gaining elevation.
Plan any mountain road trip or flight around your last dive, allowing at least 18 to 24 hours depending on how much you dived. This one habit prevents a surprisingly common cause of decompression trouble.
Or keep it warm and simple with us
Altitude diving is fascinating, but if you would rather skip the extra math and cold, sea-level diving in the Colombian Caribbean is as easy as it gets. Isla Fuerte sits at sea level with warm 27 to 29°C water and 29 dive sites, so your standard training and computer apply directly.
Prefer straightforward, sunny diving? Explore our courses and dives and our experiences around the island.
Important
This is general educational information, not medical advice. Always complete the medical questionnaire honestly, dive within your training and, if in doubt, consult a diving physician or contact DAN (Divers Alert Network). In an emergency in Colombia, the nearest hyperbaric chamber is in Coveñas.
