The real path, from the medical certificate to your first offshore job and, over the years, to the closed bell.
1) Diving medical fitness · 2) a surface-supplied commercial diving course at a school with recognised certification (HSE, ADCI, ADAS, DCBC…) · 3) first jobs, usually inshore/offshore air diving · 4) experience and logged hours · 5) a closed bell course and the jump to saturation. Nobody starts in saturation: you work up to it.
You must be of legal age and pass a diving fitness medical examination, signed by an approved diving medical examiner (in the UK, an AMED). It assesses heart, lungs, neurological system and musculoskeletal fitness, and is renewed at least every 12 months. Without that certificate you can't work. Good physical fitness and prior diving experience help.
It's the way in. You learn surface-supplied diving, the Kirby Morgan helmet, communications, decompression tables and, depending on the school, also underwater cutting and welding, hydraulic works or inspection. Choose a school whose certification is valid where you want to work.
Not all qualifications are valid everywhere. These are the major ones:
We compare all five in detail here.
You start as an air diver (inshore/inland or offshore), building up hours and learning the offshore safety culture. Over time you progress to deeper work and greater responsibilities.
With enough experience and logged hours you access the closed bell course and then saturation work. To become a bell supervisor it takes years as a bell diver, hundreds of lock-out hours and passing the IMCA exams. Very few schools in the world train saturation directly; here are the ones that do.
Being of legal age, holding a diving fitness medical certificate (signed by an approved diving medical examiner) and, in many cases, being a strong swimmer with basic recreational diving. Then the surface-supplied commercial diving course at a school with recognised certification.
The base surface-supplied commercial diving course usually lasts from several weeks to a few months depending on the country and level. Then you build offshore experience before making the jump to closed bell and saturation, which comes years later.
Practically never. Almost nobody starts in saturation: first you get the surface qualification, work offshore and, with experience and logged hours, access the closed bell course. Very few schools in the world train saturation.
The one that's valid where you want to work: HSE (UK) is the most widely accepted internationally; ADCI in the USA; ADAS in Australia and Southeast Asia; DCBC in Canada. Confirm validity before paying.
Educational guide · updated 6 August 2026