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The AIDA confined water sessions: what each level has to do in the pool

How long the static has to be, how far the dynamic has to go, and which rescues you have to practise. The confined water requirements for AIDA 1, 2 and 3 in one table, plus the fact that buddying has its own defined technique, and a certification most people do not know exists.

Safety first. This sets out what the courses require; it is not a checklist to work through on your own. Every item here — the static breath-holds above all — needs a trained person watching you. Shallow water blackout gives no warning, and a pool being shallow does not make it safer. Practising breath-holds alone is the most dangerous thing in freediving, with no exceptions.

Confined water means a swimming pool, or an enclosed body of water of comparable conditions. The AIDA courses are built so that relaxation, breathing, finning and safety procedures are learned in the pool first, then taken to open water and combined with the skills that depth requires.

Here are the confined water requirements at all three levels. Every figure comes from AIDA's official course guidelines.

The confined water requirements at each level

All three levels here follow AIDA's official guidelines, v3.4 (April 2024). Standards get revised, and outdated versions linger online for years — go by the official version your instructor is teaching to. This is here to help you understand what is being asked, not to replace the standard.

AIDA 1 has no time and no distance

Plenty of people do not realise this.

There is no "hold for this long" or "swim this far" threshold anywhere in AIDA 1's confined water requirements. Everything it asks for is "demonstrate": demonstrate the relaxation phase, demonstrate one full breath, stay relaxed during the hold, demonstrate recovery breathing, perform a static apnea safely with a buddy, and demonstrate the rescue for a buddy experiencing loss of motor control or a blackout.

So if someone tells you they are afraid to sign up because they cannot hold their breath long enough — AIDA 1 does not work that way. It asks whether you understand the procedure and do it correctly, not whether you last.

(An AIDA 1 water session may be run in a deep pool or in open water, to a maximum depth of 10 m.)

AIDA 2's two numbers: 2 minutes and 40 metres

AIDA 2 is where performance thresholds start:

• A static breath-hold of at least 2 minutes, performed safely with a buddy
• A dynamic apnea of at least 40 metres using bifins — and you have to be able to buddy one too

That second half gets overlooked. AIDA's wording is explicit: this requirement is met "both as the performing diver and the buddy." Swimming it yourself and buddying it are both examinable.

Is a 2-minute static hard?

Without any practice, yes, somewhat.

But it is worth getting the proportions right first: most people, with no practice at all, can already hold for about a minute. And the gap from one minute to two is not as frightening as it sounds.

Because what a course teaches is not endurance, it is breathing technique and relaxation technique. Once those are there, two minutes is not particularly hard. What is hard is going straight to two minutes without ever having been taught.

So if you try it now and get a minute — that is a perfectly normal starting point, not a sign this is not for you.

Why 40 metres of dynamic is the harder one

The 40 metres is horizontal distance, not depth.

What makes it hard is usually not fitness, it is body position: if you keep having to correct your posture underwater, your line through the water is not straight. A line that is not straight costs you more energy.

So people who stall at 40 metres are often not short of air. Their energy went into putting themselves back on course.

I am not only looking at whether you reached 40 metres

This part is how I do it, not an AIDA requirement.

When I am teaching, I am not only watching whether you cover 40 metres. I am watching your finning, and whether it is within what I would pass.

I am not especially strict about it. But the following are big enough problems that I would mark the technique as a fail too:

• Fins breaking the surface repeatedly — that force goes into air, not water
• Knees bending too much — kicking from the knee instead of the whole leg
• Head dropping toward the bottom of the pool
• Drifting up toward the surface

Those last two are the same problem: your body is not holding a horizontal axis, so you keep sinking or rising and then correcting back.

The reason I watch this is that if the technique is bad, then 40 metres — even when you reach it — was forced. Out at sea, with depth and pressure involved, that same technique will cost you far more. The distance is only the result. The technique is the part you take with you.

Having gone through the official documents, I found this is not just a personal preference: AIDA 3's confined water requirements explicitly ask students to refine their bi-finning technique, and specifically name "head position in body axis" and "good body posture". So body position is not written as a numeric threshold at AIDA 2, but it becomes an explicit requirement at AIDA 3. Train it early and you will not have to go back and unlearn anything.

Buddying has its own defined technique

This is the part of the guidelines I think most deserves its own section, because it is far more specific than most people expect.

For dynamic apnea, AIDA specifies the buddy procedure as:

• Swimming sideways at the surface, tracking the diver below
• Snorkel in the mouth
• Fins submerged at all times (no splashing — it obscures your view and makes noise)
• Within one arm's distance of the diver whenever the diver chooses to surface

That last point is the one that matters: not "somewhere nearby", but one arm's length. If they black out below you, you have to be able to reach them immediately.

So buddying is not standing by and watching. It is a skill in its own right, and it is assessed.

Rescue: two situations, both required

Confined water rescue covers two scenarios, and you have to be able to handle both:

LMC (loss of motor control) — the diver surfaces shaking, movements uncontrolled, but still conscious. This calls for support and stabilisation.

Blackout — loss of consciousness.

For dynamic apnea, AIDA 2 adds a specific requirement to the blackout rescue: the scenario must start underwater, and it must include removing (or simulating the removal of) all weights from the blacked-out diver.

Starting underwater, and the weights coming off first — both exist so that the diver can float.

For handling at the surface, AIDA spells it out more fully in the open water sections: secure the airway, remove the mask, and perform "blow, tap, talk" for 10 to 15 seconds.

Rescue usually comes late in the course

The way I schedule it, rescue generally comes toward the end of the teaching.

The reason is that we want you already comfortable in the water before we add it. If you are still tense looking after yourself, asking you to look after someone else just produces two people panicking.

The hard part is not bringing them up, it is keeping their head at the surface

This is the thing I most want to say, because it is not what most people imagine.

Bringing your buddy up from the bottom of the pool is not actually the difficult part. What is difficult is what comes next — keeping their head at the surface.

There are two situations:

One: there is something to lean on, such as a buoy. With a buoy available, I would have you rest their head against it. But that transfer takes some practice before you can settle their head steadily — it does not stabilise by itself just because you got them there.

Two: there is nothing to lean on. Then you have to hold their head at the surface using your own kicking, while still having enough capacity left to keep blowing on their face, calling to them, and giving rescue breaths if it comes to that.

So the genuinely tiring part of a rescue is what happens after you have got them up. Without a buoy in particular, that stretch is the hard one.

It is also why a rescue drill cannot just be the moment of pulling someone up. What decides the outcome is whether you can hold the position afterwards.

A certification most people do not know exists: AIDA2 Pool Freediver

If you meet every confined water requirement but have not completed the open water sessions — you can be certified as an "AIDA2 Pool Freediver".

This is written into AIDA's official guidelines. It is not a workaround.

For some people that is genuinely useful: living far from the sea, not being able to free up the days open water requires, or simply wanting to build the foundations properly in a pool before going out.

And the other way round: if you miss one or more confined water requirements, AIDA 1 can be issued. So even if AIDA 2 does not come together, the course was not wasted.

Why the pool comes first

One last thing about the logic of it.

The AIDA courses are not built on the idea that a pool is a simplified sea. Pools and open water train different things:

• Confined water trains relaxation, breathing, finning technique and safety procedures — none of which need depth to learn properly
• Open water is where those get combined with what depth requires: equalisation, duck dives, vertical swimming, body positioning, turns and use of buoyancy

Put another way: everything you practise in the pool you will still be using in the sea, with one extra dimension added. Get the parts that do not need depth to the point where you no longer think about them, and in the sea your attention is free for pressure, equalising and depth itself.

Recap

• AIDA 1 has no time and no distance threshold — what it asks for is that you can do it, rescue included
• AIDA 2's two numbers: a 2-minute static and a 40-metre dynamic with bifins
• AIDA 3: a 2 min 45 s static and a 55-metre dynamic
• The dynamic requirement covers both swimming it and buddying it
• Buddying has a defined technique: sideways at the surface, snorkel in the mouth, fins submerged, and always within one arm's distance
• Rescue covers LMC and blackout. AIDA 2's dynamic blackout rescue must start underwater and include removing all weights
• AIDA2 Pool Freediver is an official certification for people who pass confined water but have not done open water
• Missing one or more confined water requirements means AIDA 1 can be issued instead
• The 2-minute static: most people already have about a minute untrained, so the gap is smaller than it sounds — the course teaches breathing and relaxation technique, not endurance
• 40 metres is about position, not fitness: constantly correcting your posture means your line is not straight, and a crooked line costs energy
• I watch finning technique, not just distance: fins breaking the surface, over-bent knees, head dropping to the bottom, or drifting up all count as a technique fail
• Rescue is taught late, once you are comfortable in the water yourself
• The hard part of a rescue is after the lift: bringing someone up is not difficult; holding their head at the surface is. With a buoy, rest their head on it (that transfer takes practice); without one, you hold them with your own kicking while still blowing, calling and giving rescue breaths
• A pool is not a simplified sea: pools train relaxation, breathing, finning and safety; open water adds the skills depth requires

References

1. AIDA 1 water session requirements, 10 m maximum depth, student-to-instructor ratios, minimum of one water session — AIDA 1 Introduction to Freediving — Guidelines, Version 3.4, April 2024
2. AIDA 2 static of at least 2 minutes, dynamic of at least 40 m with bifins (performed both as diver and as buddy), minimum two confined water sessions, 5 m maximum confined water depth — AIDA2 Freediver — Guidelines, Version 3.4, April 2024
3. AIDA 2 dynamic buddy procedure: swimming sideways at the surface, snorkel in the mouth, fins submerged at all times, within one arm's distance whenever the diver surfaces — ibid.
4. The AIDA 2 dynamic blackout rescue scenario must begin underwater and include removal or simulated removal of all weights — ibid.
5. The AIDA2 Pool Freediver certification, and the provision to certify AIDA 1 where confined water requirements are not met — ibid.
6. AIDA 3 static of at least 2 min 45 s, dynamic of at least 55 m, minimum two confined water sessions, 5 m maximum confined water depth, CO2 training table, dynamic training table of at least 20 laps, neutral buoyancy for DYN — AIDA3 Advanced Freediver — Guidelines, Version 3.4, April 2024
7. AIDA 3 requires refining bi-finning technique, naming relaxation before the dive, head position in body axis, good body posture, streamlined arm positioning, turns, surfacing at the pool edge and recovery breathing — ibid.
8. Surface blackout handling: secure the airway, remove the mask, perform "blow, tap, talk" for 10–15 seconds — AIDA2 Freediver — Guidelines (open water sections)