Scuba diving, explained simply.

Equalize your ears by gently adding air to your middle ears as you descend — pinch your nose and softly blow, early and often, before you feel any pain.

Never hold your breath on scuba because the air in your lungs expands as you ascend — trapping it can over-expand and injure your lungs. Breathe continuously at all times.

Buoyancy in scuba is controlled with a BCD (buoyancy control device) and your breathing: add air to float, release air to sink, and fine-tune with your lungs to hover weightlessly — called neutral buoyancy.

Scuba diving carries real risks, but for a trained diver following the rules it's statistically very safe — most incidents come from preventable mistakes the training is designed to eliminate.

Divers can't talk underwater, so they use hand signals. Here are the essential scuba hand signals every beginner must know — OK, problem, up, down, out of air, low on air and more.

A no-decompression limit (NDL) is the maximum time you can stay at a given depth and still ascend directly to the surface (with a safety stop) without required decompression stops.

Dive tables are printed charts you use to plan no-decompression limits by hand before a dive; a dive computer tracks your actual depth and time live and recalculates your limits continuously.

An entry-level Open Water certification typically qualifies you to dive to 18 metres (60 feet). With further training you can extend your limit toward the recreational maximum of 40 m (130 ft).

An Open Water course has three parts: knowledge development (theory and a written exam), confined-water training (pool skills) and open-water dives. It usually takes 3–4 days and certifies you to 18 m (60 ft).

PADI, SSI and NAUI all produce internationally recognised, cross-honoured certifications with the same depth limits and core theory. The biggest difference is the dive centre and instructor, not the agency.

Recreational scuba builds in stages: Open Water (18 m), Advanced Open Water (30 m), Rescue Diver, then pro levels like Divemaster — plus specialties such as Nitrox and Deep.

Nitrox (enriched air) is breathing gas with more oxygen and less nitrogen than air. It extends your no-decompression limits, but has its own shallower depth ceiling because of oxygen — and needs a short specialty course.

An entry-level Open Water certification typically costs about $350–$500, depending on location, class size and what's included. Here's what drives the price and what to budget beyond the course.

You don't need to be a strong swimmer to scuba dive, but you do need basic water comfort. Most certification courses include a simple swim and float test — here's what's actually required.

Most people earn an Open Water certification in about 3–4 days of training, though it can be a long weekend with eLearning done first, or spread over a few weeks of evenings and weekends at home.

Nitrogen narcosis is a reversible, alcohol-like impairment that can affect divers at depth — usually below 30 m (100 ft) — caused by breathing nitrogen under pressure. It clears as you ascend.

Decompression sickness — 'the bends' — happens when nitrogen forms bubbles in the body after ascending too fast or staying too long at depth. It's largely preventable by diving within limits and ascending slowly.