Freediving Weighting: How to Find Neutral at the Right Depth

Freediving weighting is about choosing how much lead to wear so that you’re neutrally buoyant at the right depth: positive above it, so you float safely at the surface, and negative below it, so you sink without effort. A common rule of thumb for depth training is to be neutral at around 10 m, though some coaches set it at roughly a third of the target depth instead. In the pool the goal is different: neutral at the depth you swim. Get it right and the first metres feel easy, freefall arrives on time and the ascent stays manageable.

Most weighting problems show up the same way: a dive that feels harder than it should, at one end or the other.

What weighting actually changes

Weights don’t make you fitter or extend your breath-hold. They move the depth at which you’re neutral, and that changes how effort is spread across the dive.

• Above your neutral depth you’re buoyant, so you have to kick or pull to go down. On the way up, the water helps you.
• Below your neutral depth you sink on your own, which helps on the descent and makes the ascent heavier.

Because the air in your lungs and the gas bubbles in your wetsuit compress with depth, your buoyancy changes all the way through the dive. Our post on pressure and Boyle’s law shows how quickly this happens in the first 10 m.

Why underweighting and overweighting both hurt

Underweighted divers fight their way through the first 10 to 15 m. They kick hard, burn oxygen early, and often struggle to equalise because they’re tense and working. A clean duck dive is hard when your wetsuit behaves like a life jacket.

Overweighted divers get an easy start and a hard finish. They sink early, freefall fast, and then have to haul themselves up from well below neutral. Worse, an overweighted diver may not float at the surface.

That last point matters most. Blackouts in freediving most often happen near the surface, in the last metres of the ascent or just after surfacing. A diver who is positively buoyant there stays near the surface, where a buddy can reach them; a diver who is negative sinks. That’s why we treat “positive at the surface” as the one weighting rule that isn’t up for debate. Our post on shallow water blackout explains the physiology behind it.

The 10 metre rule and the one-third rule

There’s no perfect formula, but two rules of thumb are widely used.

1. Neutral at around 10 m. A sensible default for most recreational depth training, from the mid-teens to around 30 m. You’re positive at the surface, the duck dive and first metres take some effort, and freefall begins a little below 10 m.
2. Neutral at about a third of your target depth. For a 30 m dive that’s 10 m, so the two rules agree. For shallower dives it puts neutral shallower; for deeper dives it puts neutral deeper, which keeps the ascent from becoming too heavy.

Where the two disagree, ask your instructor. Some disciplines also change the picture: divers doing constant weight no fins often think about weighting differently because their descent starts so slowly, and spearfishers tend to weight for hanging at the shallower depths where they hunt.

Type of diving	Typical goal (rule of thumb only)
Pool dynamic	Neutral at swimming depth, around 1 to 2 m
Pool static	Floating comfortably, face down at the surface
Shallow open water, 5 to 15 m	Neutral fairly shallow, clearly positive at the surface
Depth training, roughly 15 to 30 m	Neutral around 10 m
Deeper training	Neutral around 10 m or a little deeper, set with your instructor

What changes your weighting from day to day

The same diver can need quite different amounts of lead from one session to the next.

• Wetsuit thickness. Thicker neoprene floats more at the surface and loses more buoyancy as it compresses. In the warm water around India most divers wear thin suits and need far less weight than divers in cold seas. Our wetsuit guide for Indian waters covers thickness.
• Salt. Seawater is denser than the fresh water in a pool, so you float more in the sea and need more weight there. Saltier seas, like the Red Sea, float you more again.
• Body composition. Fat floats, while muscle and bone sink. Two divers of the same body weight can need very different amounts of lead.
• Breath size. A bigger inhalation means more buoyancy at the surface.
• Suit age. Neoprene slowly compresses for good, so an old suit may need less weight than it did when new.

How to test your weighting at depth

A surface test tells you only one thing, whether you float, but check it first anyway. In full gear, with a normal full breath, you should float at the surface without effort. If you sink, you’re carrying far too much.

The real test happens at your target neutral depth.

1. Do an easy warm-up dive or two first.
2. Pull yourself down the line in free immersion to about 10 m, or whatever neutral depth you’re aiming for.
3. Stop, relax and hold the line very loosely with an open hand.
4. Notice what happens. Drifting up means you’re positive there; drifting down means negative; hanging still means neutral.
5. Surface, recover fully, and adjust in small steps. Change one thing at a time and test again.

Do this with a buddy watching, and keep the hang short. You’re testing buoyancy, not your breath-hold.

Rubber belts and neck weights

Rubber weight belts are the standard for freediving. Rubber stays snug as your wetsuit compresses at depth, unlike a nylon scuba belt that loosens and slides. Wear it low on your hips rather than at the waist, so it doesn’t slip towards your chest on head-down dives or restrict your diaphragm. It needs a quick-release buckle you can open with one hand, and the weights should be split evenly on both sides.

Neck weights are soft, horseshoe-shaped weights worn around the neck. They put weight closer to your lungs, which many divers find helps keep their legs up in the pool and their body straight on head-down dives, and they’re popular for pool dynamic. A neck weight can’t be ditched as quickly as a belt with a quick-release buckle, which is one reason many divers keep most of their weight on a belt for depth. Talk your setup through with your instructor.

Safety: Always be positively buoyant at the surface, keep your belt’s quick release clear and easy to reach, and test any new weighting only on easy dives with a trained buddy watching. Never do breath-hold dives alone, in a pool or in the sea.

Weighting in Indian pools

In a chlorinated fresh-water pool, wearing a thin suit or none, many divers need very little weight or none at all. A small neck weight is a common choice for dynamic, set so you can glide at a metre or two without rising towards the surface or settling onto the bottom. If you find yourself pressing down against the water on every length, add a little. If you keep brushing the pool floor, take some off. Our guide to pool training for freedivers has more on setting up sessions.

Weighting checklist for your next trip

• Check your weighting on the first day, at the site, in the suit you’ll actually dive in.
• Re-check whenever you change suits, move from the pool to the sea, or travel to a noticeably saltier sea.
• Write your weights, suit and neutral depth in your log so you have a starting point next time.
• Take your own rubber belt if you have one; rental belts at general dive shops are often nylon scuba belts.
• Ask the centre in advance whether they have small weights, so you can adjust in fine steps rather than big jumps.

An online community for Indian freedivers is on its way here at freediving.in, so stay tuned.