Our opinion, not professional advice. My Scuba Forum is written by recreational divers, not dive instructors, doctors or other dive professionals. Everything here is our personal opinion and general information. It is not dive training, medical advice or safety instruction. Always follow your training, your instructor, your dive operator's briefing and your doctor. Read the full disclaimer.
Most diving incidents start small: a rushed descent, a missed check, a little too much pride to call a dive. None of the tips below is new or complicated. What makes them work is doing them every time, including on the easy dives when nothing seems likely to go wrong. This guide is general information for certified divers, not training; your instructor, your agency's standards and your dive operator's briefing always come first.
Be fit to dive on the day
- Answer the medical questionnaire honestly and see a doctor who knows diving if anything on it applies to you.
- Do not dive with a cold or blocked sinuses. If you cannot equalize easily on land, you will not underwater, and forcing it risks ear injury.
- Skip the drinks the night before. Alcohol and hangovers affect judgement and hydration, both of which matter at depth.
- Drink water and eat. Hot weather, sun on the boat and dry tank air all dehydrate you.
- Be honest about how you feel. Tired, seasick or anxious is a good reason to sit a dive out. There will be another one.
Do a full buddy check, every dive
The pre-dive safety check takes about a minute and catches most equipment problems before they become underwater problems. Agencies teach it in slightly different forms; PADI's version runs in this order:
- BCD: inflator and deflator work, and the BCD holds air.
- Weights: enough weight, and the release is clear and works.
- Releases: every buckle and strap is fastened, and you both know how to undo them.
- Air: the cylinder valve is fully open, the gauge shows a full tank, and both second stages breathe normally while you watch the needle.
- Final OK: mask, fins and computer ready, and you have agreed the plan.
The air check is the one that matters most. A valve that is closed, or opened only a fraction, can feel normal at the surface and fail at depth.
Plan the dive, then dive the plan
Before you descend, agree with your buddy on the maximum depth, the maximum time, the route, the hand signals you will use, and the tank pressure at which you will turn around and at which you will begin your ascent. A common rule is to be back at the surface with at least 50 bar or 500 psi in the tank. Agree what you will do if you lose each other: the usual answer is to look around for no more than a minute, then ascend slowly and meet at the surface.
Descend slowly and equalize early
Equalize your ears gently at the surface and then every metre or so on the way down, before you feel pressure. If an ear will not clear, stop, ascend a little and try again. Never force it. Going down feet first along a line gives you more control than a head-first descent, especially for newer divers.
Control your buoyancy
Good buoyancy is a safety skill as much as a reef-protection skill. A diver who is properly weighted and in trim uses less air, stays at the planned depth, and does not crash into coral or rocket to the surface. Add small amounts of air to your BCD as you descend, and vent it as you ascend. If you often struggle, a buoyancy specialty or a session with an instructor is the best money you will spend; the scuba certification levels guide lists the courses that help.
Never hold your breath
This is the first rule of scuba for a reason. Breathe slowly and continuously, especially as you ascend, because air in your lungs expands as the pressure drops. Slow, deep breathing also cuts air use and keeps you calm.
Watch your gauge and your computer
Check your air pressure often, and tell your buddy when you reach the agreed turn pressure. Stay inside your computer's no-decompression limits with a margin to spare, and many divers set their computers to a more conservative setting, especially on multi-day trips. Narcosis can dull judgement on deeper dives, often noticeable from around 30 metres (100 feet), so keep deep dives simple.
Ascend slowly and make a safety stop
Ascend no faster than about 9 metres (30 feet) a minute, the rate many dive computers use; your computer will warn you if you go faster. When conditions and your air allow, finish the dive with a safety stop of three minutes at about 5 metres (15 feet), as your training and your computer recommend. It is a precaution, not a required decompression stop, so never let it delay surfacing in an emergency. On the surface, inflate your BCD, signal the boat, and stay with your buddy.
If something goes wrong
- Stop, breathe, think, act. Most underwater problems get worse with speed and better with a pause.
- Low on air: signal your buddy and share their alternate air source, then ascend together slowly.
- Strong current: stay low near the bottom where the current is weaker, and do not fight it; follow the guide's plan.
- After the dive: unusual tiredness, joint pain, numbness, tingling or breathing difficulty can be signs of decompression illness. Tell the crew, breathe oxygen if available, and get medical help. Divers Alert Network (DAN) runs a 24-hour emergency hotline; keep the number for your region, from dan.org, with your gear.
Flying and altitude after diving
Leave time before flying or driving over mountains. DAN's general guidance is a minimum of 12 hours after a single no-decompression dive and 18 hours after multiple dives or multiple days of diving, with longer after any dive that needed decompression stops. Most travelling divers simply keep their last full day dive-free. The dive trip planning guide shows how to build that into your itinerary.
None of these scuba diving safety tips takes long, and together they turn a good dive into a safe one. Keep your skills fresh, carry the safety gear on the scuba gear checklist, and remember that any diver can call any dive at any time, for any reason.