How to Not Float When Swimming Underwater (6 Methods)


Trying to propel yourself underwater can be a tough endeavor in and of itself. This process only gets more complicated if your body has a natural tendency toward rising to the water’s surface. Fortunately, there are ways around this problem.

You can prevent yourself from floating upwards while swimming underwater by:

  • expelling more air from your lungs
  • wearing a free diving weight belt
  • swimming deeper where there’s higher water pressure
  • swimming in fresh water, not salt water
  • reducing your overall body fat percentage
  • increasing your muscle mass percentage

All of these strategies—whether implemented exclusively or in combination—should make a tremendous difference in your ability to swim underwater and stay there. Below, we will delve into each of these methods in greater detail so that you can know exactly how to resolve this issue and improve the quality of your swimming outings.

Method #1: Expel More Air from Your Lungs

The easiest way to stop floating upward while swimming underwater is to breathe out more air from your lungs so that they’re not filled up.

Your lungs essentially act as an air-filled flotation device when they’re packed with oxygen. The more air you breathe in, the more apt your body is to float. On the other hand, the less air you breathe in, the less prone to floating you are.

It all has to do with Archimedes’ Principle. As a quick reminder, Archimedes’ Principle is the physics concept that states that any object immersed in fluid—either partially or wholly—will experience an upward buoyant force at rest. This principle goes on further to say that this upward buoyant force is directly proportional to the weight of the fluid displaced by the object (source).

If all of this sounds like scientific jargon to you, watch the clip below for a refresher on Archimedes’ Principle. The video breaks down this concept into plain English that’s easy to follow:

When your lungs are thoroughly occupied with oxygen, your chest cavity is forced to expand, causing your body to displace more water.

Since the amount of displaced water is equivalent to the magnitude of the upward buoyant force, this extra water displaced by your chest cavity increases the upward buoyant force that you’re experiencing. Consequently, your body’s natural set point in the water rises.

Think about the last time you attempted to shove a beach ball underwater. More than likely, all of your efforts to get the beach ball to rest underwater ended in vain. The weight of the displaced water was simply too much for gravity to overcome.

Exhaling oxygen from your lungs by blowing out bubbles as you swim underwater will help to reduce the upward buoyant force acting upon you. Depending on your natural buoyancy level, this practice alone may be sufficient to allow you to move as you please.

The main drawback with this method is that you won’t have enough oxygen to stay underwater for long once you get rid of enough air.

On top of that, your muscles won’t have nearly as much oxygen available to fuel your swimming activity. For these reasons, you might have to combine this method with alternative methods—or consider another strategy altogether.

Method #2: Wear a Free Diving Weight Belt

If breathing out more air doesn’t do the trick, you may have to go about manipulating Archimedes’ Principle in your favor by going to another extreme. This extreme involves the use of a free diving weight belt.

One thing you should note about the weights attached to a freediving weight belt is that they are dense. This is important because these weights will not take up that much room underwater and displace any additional fluid. This allows you to counteract the upward buoyant force by making your body artificially denser.

When wearing a free diving weight belt, you want to put on just enough weight so that you are neutrally buoyant underwater. The primary goal of this endeavor is to make your body density equivalent to the density of the water that you displace.

If you fail to put enough weight onto the belt, you will still have the problem of floating upwards. On the other hand, if you put too much weight onto the belt, your body will want to sink to the bottom of the pool, which is not something you want.

For this reason, you may have to go through a process of trial and error to figure out exactly how much weight to attach to the free diving belt, as everyone’s body composition is different. Be sure to conduct this experimentation process under the supervision of a peer to ensure your own personal safety.

When browsing through the vast selection of free diving weight belts, it may not be easy to single out just one out of the many available. To help narrow down your search, you should keep an eye out for the following features to improve your underwater swimming experience:

  • Easily Detachable – First and foremost, you need to make sure that your weight belt can be easily discarded under emergency circumstances. This way, you can resurface quickly and completely avoid the uphill battle of trying to swim back upwards. A weight belt that’s not easily detachable may invoke feelings of panic, especially if you’re in dire need of air.
  • Fitting Your Waistline – Your belt should be able to adjust to your individual waistline. Too loose and there’s a chance it may fall off underwater. Too tight and it may cause mild discomfort. Clasp-style weight belts are often preferred over the buckle-style, since you’re able to clasp the belt exactly where it’s most comfortable for you.
  • Weights that Hold in Place – You probably don’t want to have to fuss with the weights once you commit to your underwater swim. For this reason, it may be beneficial to invest in a rubber weight belt. The rubber texture prevents the weights from sliding around as you move, so you won’t have to worry about this issue whatsoever.

If you’re looking for a free diving weight belt recommendation, check out the Riffe Rubber Weight Belt on Amazon. It has all the features listed above, which sets you up for trouble-free underwater swims. Amazon also offers Sea Pearls Vinyl Coated Lace Thru Weights, which complement this belt perfectly for reliable, durable use.

Method #3: Swim Deeper Where There’s Higher Water Pressure

Another helpful strategy to bypass buoyancy issues underwater is to swim at deeper levels.

At shallow water levels, there isn’t as much pressure bearing down on your lungs. For this reason, the oxygen in your lungs remains decompressed, allowing your chest cavity to expand and displace more water, as we discussed before.

If you’ve ever swum to the bottom of a deeper pool, you’re probably aware of the fact that the pressure is noticeably higher. In fact, you may have felt this pressure in your sinuses as they tried to work towards equilibrium with the surrounding water.

This excess pressure causes your sinuses to feel strange and compresses the air in your lungs. Consequently, your chest cavity takes up less space, effectively reducing the magnitude of the upward buoyant force that’s acting on you.

This is why your body is less apt to rise toward the surface as you swim deeper underwater. Though, not many people venture toward the bottom of a pool and remain simply because it makes their sinuses feel out of whack. However, if you’re committed to eliminating your buoyancy complications, this may be a rather small price to pay, all things considered.

Method #4: Swim in Freshwater, Not Saltwater

This next tip is not well-known, but it’s a clever way to combat your body’s natural propensity towards floating while you’re swimming underwater.

If you’re used to swimming in salt water, you should experiment with swimming in freshwater. Why, you may ask?

Saltwater is slightly more dense than freshwater, as shown in the table below (source):

Type of WaterDensity Value
Saltwater1.025 g/mL
Freshwater1.0 g/mL

This is because the high amounts of salt in the water contribute mass without taking up much volume. Recall that the upward buoyant force is directly proportional to the weight of the displaced water. This slight increase in water density allows saltwater to support slightly denser objects—or in this case, humans—in water.

Thus, saltwater is marginally better at keeping swimmers at the water’s surface than allowing them to maneuver underwater. So if you struggle to swim underwater in a saltwater pool, take a dip in a freshwater pool and see if it makes a difference!

Method #5: Reduce Your Overall Body Fat Percentage

This approach may take more time and effort to accomplish, but it will be a better fix in the long run. Plus, it won’t require you to spend extra money on gear or accessories to keep you firmly underwater.

As you’ve likely gathered, body composition is a major determinant of an individual’s natural buoyancy level. Since no two people have the same body makeup, no two people have identical buoyancy levels.

One body composition factor that significantly impacts a person’s inherent buoyancy level is the amount of body fat they have. Body fat is less dense than water, as shown in the table below (source).

SubstanceDensity Value
Body Fat Tissue0.9 g/mL
Water1.0 g/mL

Objects with higher densities—like a coin—sink when placed in water. In contrast, objects with lower densities—like a balloon—float.

This is also true of humans. People with a dense body composition sink, whereas people who do not have a dense body composition float. This is the underlying reason why certain individuals do not possess the capacity to float in water.

To learn more about this contentious topic, click over to Why Can’t Some People Float? (Everything You Need to Know!).

The average human is neutrally buoyant since their body density is approximately equal to water (source).

It’s worth noting that your body weight does not affect your inherent buoyancy level. It’s all body density. This is why you should pay much closer attention to your body fat percentage measurements rather than the readings on a weight scale—that is if stopping yourself from floating underwater is your primary concern.

If weight determined buoyancy instead of density, it would be quite difficult to explain why a 1,500-ton barge can float on water while a pint-sized marble cannot.

Since people with a higher body fat percentage have a lesser body density than the average, their bodies are more naturally inclined toward floating. Put simply, the more body fat a person has, the less they will be able to stay underwater voluntarily.

By reducing your body fat percentage, you will better optimize your body composition toward neutral buoyancy. It may take a while to reach that highly sought-after body percentage, but it is one of the only permanent solutions to this flotation tissue.

Method #6: Increase Your Muscle Mass Percentage

This last method also has to do with body composition. Unlike the previous tip, however, this is not based on losing body fat. Instead, this method revolves around increasing muscle mass.

Again, the underlying premise behind this method is to increase your body density relative to the density of water. This way, your body density will fall into equilibrium with the water that you swim in, ultimately giving neutral buoyancy and the ability to move underwater with ease.

The reason you want to increase muscle mass (rather than decrease it) is that muscle tissue is denser than water, as indicated by the following table (source):

SubstanceDensity Value
Muscle Tissue1.1 g/mL
Water1.0 g/mL

Of course, muscle building is a slow, arduous process that requires weeks, and possibly months, of commitment. For some of you, such a major time commitment may not be an option. But, for others of you, this may be the solution that you’ve been looking for.

On top of improved strength, an appealing physique, and better overall health, this is yet another reason to go and hit the gym. But, again, if this solution demands too much time and effort, the other aforementioned strategies should suffice.

Sources: 1 2 3 4

Austin Carmody

I am the owner of HydroPursuit. I enjoy kicking back and getting out on the water as much as I can in my free time.

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