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.
Your certification card is your passport underwater. Dive operators everywhere ask to see it, and it tells them what depth and conditions you are trained for. The names differ a little between agencies, but the scuba certification levels follow the same ladder almost everywhere: try it, learn the basics, gain experience, learn to help others, then lead dives. The depths and ages below are the common recreational standards; your agency's current standards always have the final word.
Before you commit: the try dive
A try dive (PADI calls it Discover Scuba Diving; other agencies use names such as Try Scuba) is a short session where an instructor explains the basics, you practise a few skills in shallow water, and then you may make a shallow dive under the instructor's direct supervision. It is not a certification: you cannot dive on your own afterwards. It is a good way to find out whether you enjoy breathing underwater before you pay for a full course.
Open Water Diver: your first certification
Open Water Diver is the entry-level certification almost everyone means when they say they are "certified". It qualifies you to dive with a buddy, without a professional, to a maximum depth of 18 metres (60 feet) in conditions similar to those you trained in.
The course has three parts:
- Knowledge development: theory on pressure, equipment, planning and safety, often done online before you travel.
- Confined water: skills in a pool or pool-like water, such as clearing a flooded mask, recovering your regulator, sharing air and controlling buoyancy.
- Open water dives: usually four dives over at least two days, where you repeat the skills in the sea or a lake.
Most courses take three to four days. You will fill in a medical questionnaire first; some answers mean you need a doctor's sign-off before going in the water. Agencies also check basic water skills, typically a 200-metre continuous swim (or 300 metres with mask, fins and snorkel) and a 10-minute float or tread, with no time limit on the swim.
Children can start at 10 as Junior Open Water Divers, with extra depth limits and adult supervision, and can upgrade to the full adult card at 15. Some agencies also offer a shorter "Scuba Diver" rating that covers part of the course and lets you dive to 12 metres (40 feet) with a professional.
Advanced Open Water Diver
Despite the name, Advanced Open Water is about experience, not mastery. With PADI it is five "adventure" dives, each an introduction to a specialty; the deep dive and the underwater navigation dive are required, and you choose the other three, such as night, wreck, peak performance buoyancy or drift. PADI's Advanced Open Water Diver is trained to 30 metres (100 feet). Other agencies structure their advanced course differently, with different required dives and depth ratings, so check the agency's own standards. Many divers take an advanced course straight after Open Water, often on their first dive holiday.
Some dive sites, especially deep walls, wrecks and current dives, are only open to Advanced divers. That alone makes it a worthwhile second course for anyone planning to travel. SSI's comparable step is Advanced Adventurer.
Rescue Diver
Many divers say Rescue Diver is the most rewarding course they took. It teaches you to prevent problems, recognise stress in yourself and others, and respond to emergencies: tired divers at the surface, panicked divers, missing divers and unresponsive divers. You need a current first aid and CPR qualification, usually from the same agency's emergency first response course, completed within the previous two years. It makes you a much better buddy, even if you never use the skills in a real emergency.
Specialty courses
Specialties go deeper into one subject. The most useful for most travelling divers are:
- Enriched Air Nitrox: using gas with more oxygen than air for longer no-decompression times on repetitive dives. Many liveaboards offer nitrox.
- Deep Diver: planning and diving to the 40-metre (130-foot) recreational limit.
- Peak Performance Buoyancy: better trim and control, lower air use and fewer collisions with the reef.
- Night, Wreck and Drift Diver: the extra planning and techniques these dives need.
- Drysuit Diver: essential before diving in cold water in a drysuit.
Going professional: Divemaster and instructor
Divemaster is the first professional level. You learn to guide certified divers, assist instructors and run dive operations. You must be at least 18, hold Rescue Diver, and log a set number of dives (40 to start and 60 to finish with PADI, for example). Instructor ratings come next and let you teach and certify divers yourself.
How the agencies compare
PADI, SSI and NAUI are the best-known agencies, and RAID, BSAC, SDI and CMAS-affiliated federations are common in some countries. All the main agencies follow similar minimum standards, and dive operators around the world recognise each other's cards. The quality of your instructor matters far more than the logo on the card, so choose the shop by the people, the class size and how much time you get in the water.
| Level | Typical depth limit | Minimum age |
|---|---|---|
| Try dive (not a certification) | About 12 m (40 ft), supervised | 10 |
| Open Water Diver | 18 m (60 ft) | 10 (junior), 15 (adult) |
| Advanced Open Water Diver | 30 m (100 ft) | 12 (junior), 15 (adult) |
| Deep Diver specialty | 40 m (130 ft) | 15 |
| Divemaster | Professional rating | 18 |
Once certified, your card does not expire, but your skills fade. If it has been more than six months to a year since your last dive, book a refresher before your trip; the dive trip planning guide explains when operators ask for one. And before your first dives as a certified diver, read the scuba diving safety tips that turn course skills into everyday habits.