Backmount, sidemount or CCR?
The platform you choose shapes almost every other decision about your diving. What each one does well, where each one struggles, and how divers choose.
Read this first Information, not instruction. Nothing here replaces training with a qualified instructor.
Most technical divers end up with more than one platform over their career. The choice at any moment depends on the dives you do, the places you do them and, often, your back. There's no best configuration, only trade-offs that suit some dives better than others.
Primary platform
Which one fits your diving?
Three main ways to carry your gas.
Backmount doubles
Twin cylinders on a backplate and wing, usually joined by a manifold with an isolator valve.
Why divers choose itStable in the water, streamlined, and all your gas is available from either regulator. The default for many deep open-water and wreck dives.
Watch out forValves are behind your head, so valve drills need practice and flexibility. The manifold adds a possible leak point. Heavy to carry on land.
Sidemount
Independent cylinders clipped at your sides, each with its own regulator.
Why divers choose itValves are in front of you. Fits through restrictions. Cylinders can be carried separately, which helps on boat ladders and long walks to cave entrances.
Watch out forYou switch regulators to manage gas. Trim takes real practice, and the rig varies a lot between divers.
Closed-circuit rebreather
Recycles your breathing gas, scrubbing out CO₂ and adding oxygen to hold a setpoint.
Why divers choose itHuge gas savings, the best mix at every depth, warm moist gas, and no bubbles near wildlife or fragile wreck structures.
Watch out forComplex failure modes, strict maintenance and checklist discipline, and bailout that can outweigh the gas savings on some dives.
Backmount
Backmount doubles are the traditional technical configuration. A manifold with an isolator lets you shut down one side if a regulator fails and still breathe all your gas. That's a real advantage on deep open-water dives, where losing half your gas can be the difference between a normal ascent and an emergency.
The drawbacks are weight, reach and the manifold itself. Divers with limited shoulder mobility can find valve shutdowns hard. Some divers prefer independent doubles, with no manifold, and manage gas by switching regulators, which combines some of backmount's stability with some of sidemount's simplicity.
Sidemount
Sidemount began in caves, where divers needed to fit through tight passages and push cylinders ahead of them. It has since become popular for open-water diving too. Valves in front of you make problems easier to see and solve, and you can carry one cylinder at a time down a ladder or a long track.
The price is gas management. With two independent cylinders, you switch regulators on a schedule to keep the cylinders balanced. If one fails, you only have the gas in the other. Good sidemount divers make this look effortless, but it takes training.
Rebreathers
A rebreather changes the economics of deep diving. Instead of carrying enough trimix for the whole dive, you carry small cylinders of oxygen and diluent. That makes long, deep dives practical, and for many technical divers, a rebreather eventually becomes their main platform.
But a rebreather is also a life-support system that can fail without warning. You'll carry open-circuit bailout for every dive, follow checklists, manage scrubber life and maintain the unit carefully. Our history article on rebreathers covers how accident reviews have shaped current practice.
How to decide
- What dives do you do most? Deep open water suits backmount or CCR. Tight caves suit sidemount.
- Where do you dive? Long walks, small boats and ladders favour sidemount.
- What does your team use? Matching configurations make problems easier to solve together.
- How much time can you commit? A rebreather rewards regular diving and punishes long gaps.