Equalization is, without a doubt, one of the biggest challenges in freediving. No matter how much you improve your breathing, relaxation, or swimming technique — if equalization fails, the dive stops. It's one of the skills that most separates practitioners who progress from those who get stuck at the same depth.
There are 4 main equalization techniques in freediving: Valsalva, Frenzel, Mouthfill, and BTV. Each one has its place, its level of difficulty, and its practical application. In this post we'll introduce all 4, explain how each one works, and give an honest idea of what to expect during the learning process.
One important thing before we start: all of these techniques take time, practice, and dedication to master. There are no shortcuts. But understanding how each one works is already an important step toward knowing where you are and where you want to go.
Valsalva is the most intuitive technique and the first one most people learn — often without even knowing its name. It consists of pinching the nose and blowing with pressure, using the breathing muscles to push air toward the Eustachian tubes and balance the pressure in the ears.
How it works: you close your nostrils and push as if you were blowing your nose. The increased pressure in the upper respiratory tract forces the Eustachian tubes to open.
What it's for: it's effective in shallow water, in the first few meters of a dive. Many scuba divers and snorkelers use it successfully.
Limitations in freediving: Valsalva uses the breathing muscles — the same ones that control the lungs. As you descend and the lungs compress, it becomes increasingly difficult to generate enough pressure with this technique. In addition, the muscular effort consumes more oxygen and goes against one of the fundamental principles of freediving: relaxation. For this reason, Valsalva has a depth ceiling and, in freediving, eventually needs to be replaced by Frenzel.
Level: beginner / shallow dives.
Frenzel is the technique taught from Level 2 onwards in freediving courses and the one that opens the door to greater depths. The key difference from Valsalva is that Frenzel doesn't use the breathing muscles — instead, it uses the tongue as a piston to push air upward, while the glottis (the valve at the back of the throat) stays closed.
How it works: you close your nostrils and glottis, then try to make a "K" or "G" sound with the back of your tongue. The tongue rises and pushes a small amount of air toward the Eustachian tubes, equalizing the ears without using the air from the lungs — which is isolated by the closed glottis.
Advantages: because it doesn't depend on the lungs, it works even at depths where Valsalva can no longer generate enough pressure. It's more efficient, consumes less oxygen, and is more compatible with the relaxation needed in freediving. With training, it can be used effectively to 20–30 meters or more.
Difficulty: this is where most intermediate practitioners get stuck. Frenzel requires awareness and control of muscles we never use in isolation in everyday life — the glottis, the soft palate, the base of the tongue. It can't be learned only in the water: it requires dry practice, sometimes with specific tools, and can take weeks or even months to perform consistently. Taking time is completely normal.
Level: intermediate / from 10–15 meters.
Mouthfill is an evolution of Frenzel created to solve a specific problem at great depths: from a certain point (usually around 30–40 meters), the lungs are so compressed that there is no longer enough air to feed Frenzel. Mouthfill solves this by storing a reserve of air in the mouth before reaching that depth.
How it works: at a specific depth during the descent — usually between 15 and 20 meters, while there is still air available in the lungs — you take one last "charge" of air into your mouth and cheeks. Then you close the glottis completely, isolating that air from the lungs. From that point on, all equalization is done using only the air stored in the mouth, with the tongue movement of Frenzel.
What it's for: it's the technique that allows diving beyond 30–40 meters consistently and safely.
Difficulty: high. It requires Frenzel to already be well established, as well as precise control of the glottis and the right timing for the air charge. It's one of the most challenging techniques in freediving and requires guidance from an experienced instructor.
Level: advanced / from 30–40 meters.
BTV — whose name comes from French and means "voluntary tubal opening" — is considered the most advanced and also the most difficult technique to learn. The idea is to open the Eustachian tubes directly through muscular control, without needing to move any air. When it works, equalization happens almost automatically, simply by opening the tubes.
How it works: through direct control of the muscles surrounding the Eustachian tubes, the practitioner learns to open them voluntarily, without blowing or using the tongue.
Advantages: when mastered, it's the most efficient technique of all — it consumes no air, requires no effort, and can be maintained continuously throughout the descent.
Difficulty: very high. It's estimated that only around 30% of people can learn it reliably, even with specific training. It's not taught in standard courses and requires very specific work on muscular awareness.
Level: advanced / elite.
The answer depends on your depth and current level:
| Depth | Recommended technique |
|---|---|
| 0 to 10m | Valsalva (works, but start learning Frenzel) |
| 10 to 30m | Frenzel |
| 30m or more | Mouthfill |
| Any depth | BTV (if you can learn it) |
In practice, the development path for most practitioners is: Valsalva → Frenzel → Mouthfill. BTV is more of a rarity than a mandatory goal.
None of these techniques — especially Frenzel and Mouthfill — are learned quickly. They require dry practice, consistency, sometimes support tools, and a lot of patience. It's completely normal to get stuck on Frenzel for weeks. It's completely normal to feel like "nothing is happening." The process is part of it.
The most important thing is not to force equalization when the ears won't open. If you feel pain, ascend immediately — never force it. A ruptured eardrum is a serious injury that can take months to recover from and, in severe cases, cause permanent damage.
We'll soon be publishing a practical guide with dry exercises to train Frenzel — because we know that's exactly where most practitioners need support.
Want to know more about the world of freediving? Also read: [Freediving: Mind and Body Benefits] and [Freediving Course in Porto de Galinhas: Complete Guide 2026]