Closed-circuit rebreathers recycle breathing gas and continuously manage the breathing loop's composition, removing carbon dioxide with a scrubber and adding oxygen as it is consumed.
The benefits are substantial: long gas duration largely independent of depth, near-silent operation with minimal bubbles, warm moist breathing gas and an optimised oxygen partial pressure throughout the dive.
The risks are equally real and are different in kind from open-circuit diving. CCR training is unit-specific, and so is the support a dive centre can provide.
Closed Circuit Rebreather Diver: learning topics
loop assembly, pre-breathe and pre-dive checks
Discuss how this topic is taught and assessed within the exact programme.
oxygen partial pressure monitoring and manual control
Discuss how this topic is taught and assessed within the exact programme.
scrubber packing, duration and monitoring
Discuss how this topic is taught and assessed within the exact programme.
diluent management and depth limits
Discuss how this topic is taught and assessed within the exact programme.
bailout planning and execution
Discuss how this topic is taught and assessed within the exact programme.
failure recognition and response
Discuss how this topic is taught and assessed within the exact programme.
Topics recorded in this general course guide, not training instructions or a statement of automatic eligibility. Confirm the programme’s current scope with its agency.
What the course covers
- loop assembly, pre-breathe and pre-dive checks
- oxygen partial pressure monitoring and manual control
- scrubber packing, duration and monitoring
- diluent management and depth limits
- bailout planning and execution
- failure recognition and response
The risks are different, not merely greater
Open-circuit diving fails obviously — a regulator free-flows, a cylinder empties. Rebreather failures are frequently silent, and the diver may feel fine while the loop becomes unbreathable.
Support is unit specific
CCR support is not a single capability. A centre may service one manufacturer's units, stock a particular sorb, and have instructors qualified on specific models.
A centre page should name supported units where possible, because a rebreather diver arriving with the wrong unit has no support at all.
Common questions
Is a rebreather worth it for recreational diving?
For most recreational divers, no. The cost, maintenance burden and training commitment are substantial, and the benefits are most valuable on long, deep or wildlife-sensitive dives.
Can I get sorb and support anywhere in Australia?
Support is concentrated in the major cities and specific technical centres, and is unit-dependent. Confirm both sorb availability and unit support before any trip.
Which unit should I train on?
Consider what your local centre supports and services, because ongoing support matters more than the initial purchase decision.