Rebreather vs. Regulator

Every diver uses a regulator. You go underwater, you breathe and the bubbles surround you. Not so with a rebreather. There are no bubbles and everything is quiet.

Differences between Scuba Regulator and Rebreather Diving

Eerie? Kind of…

So, besides the bubbles, what are the differences between a rebreather and a regulator? What are the pros and cons?

Let’s dive right into it!

What is a Rebreather?

A rebreather is a piece of scuba gear that allows you to breathe underwater using smaller air tanks. It does this by recycling the air you breathe over and over again. When you breathe in using a rebreather system, you’re getting your air from several different places.

First, the rebreather removes exhaled carbon dioxide from the air you breathe out through the use of a canister of sodium hydroxide gas. The two gases mixed to form a solid called calcium carbonate.

Next, a small tank of pure oxygen or mixed gases (nitrogen and oxygen or helium and oxygen) will inject fresh air into your breathing loop. This is called a closed-circuit breathing system because none of the air ever leaves the system.

Hollis Explorer Rebreather

​A rebreather uses computers to calculate the partial pressure of oxygen within the breathing circuit. This information is sent through the control system and allows the rebreather to know how much oxygen or gas mix to deliver into the breathing loop.

Depending on the type of rebreather you have you can spend great lengths of time at depth. Completely closed-circuit rebreathers allow you to dive at greater depths for greater lengths of time because your air is not pressure dependent. If you are using an oxygen rebreather that carries only a cylinder pure oxygen, you may be limited to no decompression stop depths.



  • Failures Can Go Unnoticed
  • Higher Maintenance
  • Higher Cost

Best to use

Rebreathers are typically used by divers who want to have greater dive times or spend more time at depth. They have been very popular with technical and professional divers for a long time.

Also, if you like to dive with gas mixes, a rebreather is going to be able to provide you with better control over those mixtures. Rebreathers have superior computing capabilities for optimizing the gas mix.

Diving with a rebreather

People who want to blend in with their environments seamlessly or be able to sneak up on a photography target may prefer a rebreather because it is not as loud as an open circuit regulator. The lack of bubbles makes rebreather’s very quiet.

People who have throats that get very irritated with the dry air of a regulator may be able to dive more comfortably with the rebreather because of the moist warm air that rebreathers provide. The recirculated air is completely different than the type of air you get from a regulator.

What is a regulator?

The regulator of your scuba gear is directly attached to your air tank through a high-pressure hose. This means every time you take a breath from your regulator, you get a lungful of air directly from your tank.

When you breathe out the air is exhaled and goes through the regulator into the water in the form of bubbles. This is what divers call and open circuit system.

Diving with a regulator - bubbles all around

None of the air that you breathe when using a regulator is recycled. You breathe in the fresh air every single time you take a breath and exhale it directly into the water.

This means you have a set amount of air to use. Once the amount of air you filled up in your tank is gone, it’s gone, and you have no way of refilling it until you surface.


  • You Can Use a Backup
  • Fresh Air Every Time
  • Simple to Use
  • Require Less Maintenance


  • Bottom Time Limited
  • Air Is Pressure Dependent
  • Less Accurate Gas Mix Control

Best to use

Regulators are ideal for people who are just getting into diving. Chances are you’re not looking for the most expensive equipment. You’re not going to be diving at great depths. And you’re not going to be diving with technical gas mixes.

People who like to have a backup plan are going to be much more comfortable using a regulator system then they are using a rebreather. When a rebreather brakes down at depth, it can be a life-ending event.

However, if your regulator breaks down at depth, you will likely have your spare on hand, or you can share it with your dive buddy. If you’re a person, who values redundancies for safety reasons you definitely want to use a regulator over a rebreather.

Some people don’t like the way that the rebreather’s air tastes. While it is warmer and moister, it can taste quite different than the air you get off the regulator. This is a personal choice, but it may be one that makes or breaks whether or not you get a regulator or rebreather.

Hollis Rebreathers

What are the differences?

Regulators and rebreathers are completely different systems. Aside from the fact that they both allow you to breathe underwater, they have very little in common.

A regulator will give you fresh air every breath you take but provides you with minimal bottom time. The rebreather gives you maximum bottom time, but you don’t get that same fresh air.

There are also differences in cost and maintenance. A regulator requires less maintenance than a rebreather, it costs less, and if it fails; it is less life-threatening. While both systems are great, you will have to decide for yourself which one is best to use.

Differences between Scuba Regulator and Rebreather Diving
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