What to expect in your Open Water course
Updated 2026-06-30 · Certification
An entry-level Open Water course is built around three parts: knowledge development (the theory, ending in a written exam), confined-water dives (practising skills in a pool or pool-like water), and open-water dives (usually four dives in the sea or a lake). Most courses run over 3–4 days, and at the end you're certified to dive to 18 m (60 ft) with a buddy.
Knowing the shape of the course ahead of time takes away most of the nerves — especially the theory part, which is the piece most beginners worry about.
1. Knowledge development (the theory)
You'll learn how pressure affects your body and gear, how to plan dives within no-decompression limits, how your equipment works, and what to do in an emergency. It ends in a multiple-choice written exam — the part this site's study system is built to make easy. Understand the why and the exam feels obvious.
2. Confined water (pool skills)
In shallow, calm water you'll practise the core skills until they're second nature: clearing a flooded mask, recovering your regulator, sharing air with a buddy, and controlling your buoyancy. There's usually a basic swim and float test too. Mistakes here are expected — that's the whole point.
3. Open-water dives
Finally you apply everything across about four open-water dives with your instructor, gradually doing more on your own. To enrol you'll typically need to be 10 or older (Junior certifications apply under 15) and complete a short medical questionnaire. Pass all three parts and you've earned a certification that's recognised worldwide.
Frequently asked questions
How long does it take to get Open Water certified?+
Most courses take 3–4 days, split between theory, pool sessions and open-water dives. Some are spread over a few weekends, and you can often do the theory online beforehand to shorten the in-person time.
Is the Open Water exam hard?+
It's a multiple-choice written test on core theory — physics, equipment, planning and safety. It's very passable when you understand the concepts rather than memorising, which is exactly what a good study system gives you. Most agencies back it with a retake if needed.
Do I need to be a strong swimmer?+
You don't need to be an athlete, but you'll do a basic swim and a float/tread test to show you're comfortable in water. Being relaxed in the water matters more than speed.