Confined Water Dives: What to Expect

The pool is where you first put on scuba gear and breathe underwater. Here's what happens, what skills you'll learn, and how to walk in feeling prepared.

Why the pool matters more than people expect

Most prospective divers are eager to skip to the ocean dives. The pool sessions feel like a prerequisite: the thing you have to get through before the good stuff. That is the wrong frame.

Your pool sessions are where scuba diving becomes real. Everything you read in your theory (how a regulator works, how to equalise, what neutral buoyancy feels like) turns from abstract into physical. The skills you practise in the pool are the same ones you'll use on every dive you make. The only difference is that if something goes wrong in shallow water, you can stand up.

That margin for error is exactly why the pool is valuable. It is a safe place to get things wrong, repeat them, and get them right. Use it.

What confined water training actually is

Confined water training is the name certification agencies give to the pool part of your Open Water course. "Confined" means water with pool-like conditions: usually a swimming pool, though some schools use very shallow, sheltered water or purpose-built dive training pools.

What makes it confined is clear water, no current, a depth you can control and your instructor close by. SSI, for example, caps pool and confined water training at 5 metres. This is deliberately the least challenging diving environment possible. The point is learning, not challenge.

What the pool looks like and what happens when you arrive

Some dive centres have their own training pools. Pro Dive Cairns has two heated, 4-metre-deep training pools at its city training centre, Dive Centre Manly has its own training pool, and Adelaide Scuba has an on-site heated pool. Others use public pools: Pro Dive in Sydney uses Victoria Park Pool near Broadway, and Dive Centre Bondi a heated 50 m pool.

Your instructor will introduce you to your scuba equipment before you get in: identifying each component, explaining what it does, and walking you through how to put it together. You will not be expected to remember everything at once. The assembly becomes automatic after a few repetitions.

You will then do a buddy check (PADI calls it the predive safety check) with your buddy and instructor, and get in.

Getting into scuba gear for the first time

The first thing most new divers notice when they put on a scuba set is how heavy it is on land. Walking to the pool edge in fins while managing all of it feels awkward.

The second thing they notice is that once they are in the water, the weight stops mattering. The water supports it.

What to expect when you put on the gear for the first time:

- The BCD (buoyancy control device, the inflatable jacket) fits like a vest and feels more constrictive than expected, especially once the tank is attached. This is normal, and it feels lighter once you are in the water. - The regulator mouthpiece feels slightly large at first. Most people forget it within a minute of breathing from it. - The mask creates a sealed feeling around your face. If it isn't sealing, water will trickle in straight away, which is exactly the kind of thing you want to discover in a pool rather than the ocean. - Fins make walking on dry land very awkward. Shuffle backwards rather than forwards near the water's edge so you don't trip on them.

Your first breath underwater

For most people, the first breath from a scuba regulator underwater is the moment that changes everything: the sudden understanding, physically and not just intellectually, that breathing underwater is possible.

Your instructor will introduce this in shallow water, where you can kneel or stand. You put the regulator in your mouth, put your face in the water and simply breathe. There is no complicated technique. Air comes when you inhale. Your exhaled breath leaves as a stream of bubbles.

Some common first reactions:

- A moment of hesitation before the first inhale: entirely normal, and it passes. - Breathing slightly faster than usual: excitement and nerves raise your breathing rate. It settles as you relax. - A slightly different feel to each breath: breathing through a regulator is not quite like breathing on land, and most people soon stop noticing. - An urge to smile: the regulator makes this difficult, but your instructor will see it in your eyes.

The skills you'll learn and why each one exists

PADI's course has five confined water sessions, taught in a set order, and you master each skill in the pool before you do it in open water. Other agencies teach the same core skills in their own order. Here is each one, and why it matters in real diving.

Equipment assembly and pre-dive checks Why: a gear problem you catch on the surface is an inconvenience. One you discover underwater is a problem. The buddy check catches common issues such as a valve not fully open or a weight belt not secured before you get in.

Clearing a flooded mask Why: masks flood. A buddy's fin can knock yours, or a hair under the seal can let water in. The skill: keep breathing slowly through your regulator, hold the top of the mask frame against your forehead, look up slightly and breathe out steadily through your nose. The air pushes the water out of the bottom. On PADI's course you start with a partly flooded mask, then a fully flooded one, and practise until it is routine.

Recovering a lost regulator Why: a regulator can be knocked out of your mouth by a buddy, a wave or your own hand catching the hose. The skill: blow a small, steady stream of bubbles, lean a little to your right and sweep your right arm down past your thigh, then out and round in a big circle forward. The hose ends up across your arm; follow it to the mouthpiece. If the sweep misses, reach back over your right shoulder to the first stage on the tank and follow the hose forward. PADI covers this in the first pool session.

Clearing water from the regulator Why: water gets into the mouthpiece whenever it comes out of your mouth. The skill: breathe out firmly into it (a small puff is often enough) to push the water out, or, if you are short of breath, block the mouthpiece with your tongue and briefly press the purge button. Breathe in cautiously and purge again if water remains.

Buoyancy control Why: neutral buoyancy, staying at one depth without sinking or floating up, saves air, protects the reef from accidental contact and makes every dive easier. In the pool you first learn to rise and fall a little with each breath, then to hover without kicking or sculling (at least 30 seconds on PADI's course), and later to hover after inflating your BCD by mouth. Most students are erratic at first. That is the point.

Equalising pressure Why: covered in your theory, practised physically here. You pinch your nose through the mask's nose pocket and breathe out gently against it, or swallow, to equalise the pressure in your ears. In shallow water you may barely feel the need, but practising the technique here means it's ready on your first descent to as much as 12 metres in open water. Our equalisation guide goes further.

Sharing air with an alternate air source Why: your regulator set includes a spare second stage, the alternate air source (or "octopus"), so you can give air to a buddy who has run out. On PADI's course you breathe from a buddy's alternate for at least 30 seconds in shallow water in the first pool session, later swim while breathing from it for at least a minute, and practise giving air as well as receiving it.

Controlled emergency swimming ascent (CESA) Why: it simulates what to do if you have no air and no buddy within reach. You keep the regulator in your mouth and breathe out continuously while making a long "aaah" sound, which keeps your airway open so the expanding air in your lungs can escape. In the pool, PADI students practise it by swimming horizontally or on a slant for at least 9 metres while making a continuous sound. The real ascent is practised later, in open water, starting from 6 to 9 metres with your instructor holding you.

Mask removal and no-mask swimming Why: masks can come off, and knowing you can manage without one turns a fright into a minor adjustment. On PADI's course you take the mask off, put it back on and clear it, breathe without a mask for at least a minute, and later swim at least 15 metres without it before replacing and clearing it. More disorienting than expected; more manageable than feared.

Weight and BCD skills Why: your weights and BCD decide whether you sink, float or hover. You do a weight check (with little or no air in the BCD and a normal breath held, you should float at about eye level), take your weights off and put them back on, and practise dropping weight in an emergency.

How long it takes and how many sessions

Schools run the pool part in different ways:

- One long pool day: Underwater Sports in Adelaide runs a five-to-six-hour pool day, and Divers Den's eLearning course in Cairns puts at least eight hours of in-water training into one day. - Spread over two days or sessions: Snorkel and Dive Safari in Melbourne runs more than five hours of pool training over two days, and Ocean Divers includes up to eight hours in a heated pool.

Your pool sessions are almost always done on day one, or spread across the first two days of your course, before the open water dives.

What assessment looks like

Pool sessions are assessed by your instructor throughout. Your instructor watches you demonstrate each skill and either signs it off or asks you to repeat it.

PADI defines mastery as doing a skill in a reasonably comfortable, fluid and repeatable way. Not: did you do it perfectly on the first try. PADI students also mark on a slate whether they are comfortable with each skill or want more practice.

Repeating a skill is not a sign of failure: it is the course working as designed. Schools differ on what happens if you need more time, though. Diveline charges to repeat a day if you don't meet its skill requirements, and Bucket List Diver in Perth charges $200 to rejoin a later pool session, so ask before you book.

Common difficulties and how instructors handle them

Mask anxiety: some students find the sealed feeling of a mask uncomfortable, or feel panicky when it floods during clearing practice. Water around the nose makes many people hold their breath, so keep a slow, steady breathing rhythm going. A good instructor introduces mask clearing in small steps (a partial flood first, then a full flood) and gives you as many repetitions as you need. If this is a concern, mention it before the session begins.

Equalisation not working in the pool: the pool is shallow enough that you may not feel much ear pressure, so equalising in the pool is partly about learning the technique rather than feeling the need. Some students find it clicks straight away; others need a few attempts.

Buoyancy frustration: many students add too much air to their BCD, float up, then let too much out. The correction is always the same: less air, smaller adjustments, more patience, and let your breathing do the fine-tuning.

Regulator breathing that feels effortful: a regulator should not feel like hard work. If it does, tell your instructor: it may need checking, or your breathing pattern may need adjusting.

Tips for getting the most from your pool sessions

Arrive early and spend a few minutes with the equipment before your instructor's formal introduction. Familiarity makes the first session less overwhelming.

Tell your instructor what concerns you before the session starts. Anxiety about mask clearing, a closed-in feeling in the gear, nervousness about breathing underwater: instructors hear all of these regularly and can adapt to them, but only if they know.

Breathe slowly and continuously. Never hold your breath on scuba. Old snorkelling habits and nerves both make people hold their breath, so remind yourself before every skill.

Do not rush the buoyancy practice. It is tempting to declare "good enough" and move on. Buoyancy shapes how much you enjoy every dive you make. Our buoyancy guide has more tips.

Take notes after each session. What worked, what needs more work, what questions came up. Reviewing these before your ocean dives gives you a target rather than a vague sense of anxiety.

After the pool, read Open Water Training Dives: What to Expect.

Sources

- PADI: Instructor Manual, 2021 edition - PADI Blog: How to clear your mask - PADI Blog: Master underwater mask removal - PADI Blog: How to recover your regulator when diving - Scuba Diving magazine: How to Recover and Clear Your Scuba Regulator, scubadiving.com (blocks simple scripts; read 14 October 2026) - PADI Blog: Buoyancy control - SSI Training Standards: Referral Diver - DAN: Emergency ascents, managing the risks - Pro Dive Cairns: 4 Day eLearning PADI Open Water Course - Pro Dive: Learn to Dive Sydney - Dive Centre Bondi: PADI Open Water Course - Dive Centre Manly: PADI Open Water Course, divesydney.com.au (blocks automated requests; read in a browser on 13 October 2026) - Adelaide Scuba: Our Facilities, adelaidescuba.com.au (blocks plain scripts; read 14 October 2026) - Underwater Sports Diving Centre: Learn to Scuba Dive in Adelaide - Divers Den: PADI eLearning Open Water Course - Snorkel and Dive Safari: Open Water Scuba Diver Course - Ocean Divers: Open Water - Diveline Scuba Centre: PADI Open Water Diver Course - Bucket List Diver: PADI Open Water course, Perth

Header photo: Scouts Canada members learning to scuba dive in a swimming pool, by CDNScouter, CC BY-SA 3.0, via Wikimedia Commons.