Dive safety rules every new diver learns

The core rules

1. Breathe continuously. Never hold your breath on scuba. Expanding air in your lungs during an ascent can cause serious injury.
2. Equalize early and often, and never force it. If an ear won't clear, rise a little and try again, or end the dive.
3. Plan the dive and dive the plan. Agree on maximum depth, time, turn point, gas reserve and signals before you get in.
4. Stay with your buddy. Keep close enough to reach each other, and agree what to do if you get separated.
5. Watch your gas. Check your gauge often, turn the dive at the agreed point and reach the surface with the reserve you planned.
6. Ascend slowly. Your course sets a maximum ascent rate, often about 9 m (30 ft) a minute, and usually teaches a safety stop of about 3 minutes at about 5 m (15 ft).
7. Control your buoyancy. Most incidents with gear and the reef start with a diver who is sinking or rising without meaning to.
8. Don't dive when unwell, tired, dehydrated or after alcohol. If in doubt, sit it out.
9. Allow time before flying or going to altitude. Published guidelines set minimum waits after diving. Follow them and your computer.
10. Know the emergency plan. Where the oxygen and first aid kit are, who to call and how to get help from the site.

Why you never dive beyond your training

A certification card describes what you were trained for: roughly how deep, in what kind of conditions and with whom. Going past that isn't a small step up. Several things change at once.

• Gas runs out faster. At 20 m you breathe about three times as much gas per breath as at the surface, so a deeper dive leaves less margin for problems.
• Your thinking slows down. Nitrogen under pressure has a narcotic effect that can dull judgment as you go deeper, often without you noticing.
• Time limits shrink. The deeper you go, the less time you can stay before a direct ascent is no longer advised.
• The way out gets longer. A problem at depth takes longer to solve, and a fast ascent carries real risks.
• Some places have no direct way up. Caves, caverns and the inside of wrecks have a ceiling over you. They need specialized training and equipment.

Each step beyond your training should come through a course with an instructor, then plenty of practice. Ask a certified instructor before you try deeper water, a new environment or new equipment, and read your training agency's own materials on depth and conditions.

If something feels wrong after a dive

Any unusual symptom after diving deserves medical attention. That includes pain, numbness, tingling, unusual tiredness, dizziness, trouble breathing or confusion. Get medical help quickly, and tell the medical staff you have been diving and give your dive details. Dive safety organizations run emergency advice lines, and dive centers usually keep the local number posted. Your course covers first aid steps such as giving oxygen, which you should only do if trained.

This page is general information. It is not training, and it is not medical advice. Your instructor, your training agency's materials and a doctor are the right sources for anything that affects your safety.

Dive safety FAQ