Commercial diving certifications, compared
Which scheme opens which ocean - and why IMCA does not certify divers at all.
IMCA does not certify divers. It certifies diving supervisors and life support technicians, and it recognises nine national schemes: ADAS (Australia), DCBC (Canada), NDC-CI (Netherlands), WorkSafe (New Zealand), Havtil (Norway), the Department of Employment and Labour (South Africa), HSE (UK), and ACDE and ADCI (USA). If your certificate does not come from one of those, it does not open offshore work under the IMCA code — and an inland or inshore certificate never does, whoever issued it. In the UK North Sea specifically, HSE Surface Supplied is not enough on its own: you need the Top-Up.
- What IMCA does and does not do
- UK — HSE
- USA — ADCI
- Australia — ADAS
- Canada — DCBC
- France — CAH
- Norway
- South Africa
- Brazil, India and the rest
- The schemes side by side
- Reciprocity: what works where
- Supervisor and LST certification
- Who is who: the alphabet soup
- Converting between schemes
- How to verify a certificate
- Questions
What IMCA does and does not do
This is the single most misunderstood thing in commercial diving, and schools misstate it constantly. IMCA — the International Marine Contractors Association — set out its own position in Information Note 1609 of April 2022: IMCA issues air and bell diving supervisor and life support technician certificates only.
It does three things that matter to a diver:
- It publishes the code. The IMCA International Code of Practice for Offshore Diving (D 014) and the D-series guidance documents are the de facto rulebook of offshore diving worldwide, even though IMCA is a trade association with no legal authority anywhere.
- It certifies supervisors and LSTs. Two schemes, each with its own route and exam.
- It recognises national diver schemes. This is the gate that determines whether your certificate is worth anything offshore.
The recognised list
IMCA recognises offshore diver training certificates issued by these authorities for operations conducted under its code:
| Country | Authority | Scope |
|---|---|---|
| Australia | ADAS | Offshore |
| Canada | DCBC | Offshore |
| Netherlands | NDC-CI | Offshore |
| New Zealand | WorkSafe | Offshore |
| Norway | Havtil | Offshore |
| South Africa | Department of Employment and Labour | Offshore |
| United Kingdom | HSE | Offshore |
| United States | ACDE and ADCI | Offshore |
| Singapore | DCA | Inland and inshore only |
The acceptance criteria behind the list
IMCA Information Note 1385 of March 2023 sets out what a scheme has to meet. Surface-supplied training must satisfy IDSA Level 3 ("Surface Supplied Offshore Air Diver") or IMCA's own minimum criteria; saturation training must meet the IDRCF Closed Bell Diver Training standard. The certifying body must be an IDRCF member, a member of another international standards body IMCA recognises, or directly recognised by IMCA. IMCA also requires that the training be open to all and directed at developing divers for offshore operations — which is why military-only schemes do not appear on the list.
Information Note 1384 spells out the minimum content for surface-supplied training: theory and practical, operations from both cage or stage and wet bell, decompression dives using both in-water and surface decompression, chamber operation, at least ten commercial SCUBA dives to a maximum of 30 m, dives as both diver and standby diver to a maximum of 50 m, first aid, and underwater rigging and tool tasks.
UK — HSE
The legal basis is the Diving at Work Regulations 1997, under which HSE approves diving qualifications it considers suitable for ensuring adequate competence.
| Qualification | What it permits |
|---|---|
| HSE Professional SCUBA | Commercial SCUBA, inland and inshore |
| HSE Surface Supplied | Surface-supplied diving to 50 m |
| HSE Surface Supplied (Top-Up) | Adds the offshore competences: wet bell, hot water suit, bell and standby operations. This is the offshore gate |
| HSE Closed Bell | Closed bell and saturation diving |
Two facts about HSE certificates that matter:
They never expire. HSE states plainly that its diving qualifications are not renewable and are valid indefinitely. But contractors must still assess competence on recency of experience, so an old certificate with no recent logged dives is not a working qualification.
HSE does not issue them. Certificates are issued by HSE-recognised Diver Competence Assessment Organisations. The organisations listed as of early 2026 were: Andark Diving & Watersports; Bristol Channel Diving Services; Commercial Diver Training Ltd; Defence Diving School; D.V. Diving; Northumbria Police International Diving School; Police Scotland National Diving School; Puffin Dive Centre; Ramora Global; TH Diving Services; The Professional Diving Academy; and the University of Plymouth.
HSE also publishes a List of Approved Diving Qualifications — current edition dated 1 January 2025 — which approves foreign qualifications as well. For Closed Bell, offshore only, it recognises qualifications from Great Britain, Australia, Canada, France, the Netherlands, Norway, South Africa and Sweden. The Surface Supplied list is wider.
USA — ADCI
The American route is experience-gated rather than course-gated after entry, and the numbers are specific. All dives counted must fall within the 24 months immediately before issuance; cards are valid five years, except entry level, and must be obtained within 90 days of employment with an ADCI general member company.
| Grade | Requirement |
|---|---|
| Entry Level Tender/Diver | At least 625 documented hours of formal instruction to ANSI/ACDE-01-2015 |
| Air Diver | 100 field days as air diver + at least 30 working dives, surface supplied only |
| Mixed-Gas Diver | 100 air + 50 mixed-gas field days; 50 air + 10 mixed-gas working dives |
| Bell/SAT Diver | 200 field days (air or mixed gas) + at least 100 working dives + 10 bell runs + 30 working days supporting bell or saturation operations |
| Air Diving Supervisor | 200+ field days as air diver, 50+ working dives, 30 days as assistant supervisor, online exam |
| Mixed-Gas Diving Supervisor | 350 field days, 150+ working dives, 30 days as assistant supervisor, exam |
| Bell/SAT Diving Supervisor | 100 field days as mixed-gas supervisor + 60 days as assistant supervisor, exam |
| Life Support Technician | 100 field days as assistant LST, exam |
The governing document is the ADCI International Consensus Standards for Commercial Diving and Underwater Operations, currently edition 6.5.
The International Endorsement, and why it may not help you
A joint ADCI/IMCA arrangement effective 1 August 2018 created three IMCA-recognised ADCI certificates. Two caveats matter: it is available only to US residents, and ADCI's own page has continued to state that no IMCA-recognised ADCI surface-supplied certifications have been issued. In practice, US-trained divers heading for the North Sea usually take an HSE Surface Supplied Top-Up or a full conversion. If this route matters to your plans, verify the current position with IMCA directly rather than relying on any page, including this one.
Australia — ADAS
| Part | Scope |
|---|---|
| Part 1 | Occupational SCUBA to 30 m |
| Part 2 | Surface supplied breathing apparatus to 30 m |
| Part 3 | SSBA to 50 m — the offshore air diver level |
| Part 3 + SSMG | Adds surface supplied mixed gas to 75 m |
| Part 4 | Closed bell — to 300 m, closed bell and saturation systems |
A hard rule: to hold Part 2 or Part 3 you must also have been trained and assessed competent in SCUBA to 30 m. Part 4 references AS 2815.4 (Closed Bell Diver) and the Certificate IV in Hyperbaric Operations.
ADAS is an IDRCF member and recognises its partners — but with expiry cliffs worth noting: French licences only if issued before 14 June 2024, South African licences only if issued before 30 June 2010. Military crossovers exist for the Royal Australian Navy (pre-March 2012), Australian Army (pre-August 2017) and the Royal New Zealand Navy.
Canada — DCBC
The Diver Certification Board of Canada issues one of the most granular certificate sets in the world.
| Category | Certificates |
|---|---|
| Divers | Occupational SCUBA Diver · Restricted Surface Supplied Diver (30 m) · Unrestricted Surface Supplied Diver (50 m) · Surface Supplied Mixed Gas Diver (70 m) · Closed Bell Diver (over 70 m) |
| Supervisors | SCUBA Supervisor · Restricted Surface Supplied Supervisor · Inshore Air Diving Supervisor · Offshore Air Diving Supervisor · Surface Supplied Mixed Gas Supervisor · Bell Diving Supervisor |
| Support | Surface Supplied Tender · Hyperbaric Chamber Operator · Hyperbaric Life Support Technician · Life Support Supervisor |
| Other | ROV Pilot/Technician levels 1, 2, Senior and Supervisor; Inshore and Offshore Diving Safety Specialist |
DCBC also operates a formal crossover route for holders of foreign certificates, which is one of the cleaner conversion paths available.
France — CAH
France uses a two-axis system that confuses everyone who meets it for the first time. The Certificat d'Aptitude à l'Hyperbarie combines a Classe (depth) with a Mention (activity), and both must match the work.
| Classe | Depth | Mention | Activity |
|---|---|---|---|
| 0 | to 12 m | A | Underwater construction and public works — maritime, petrochemical, civil engineering |
| I | to 30 m | B | Interventions: archaeology, rescue, sport, media |
| II | to 50 m | C | Health sector, non-immersion |
| III | beyond 50 m | D | Non-immersion hyperbaric work: tunnelling, welding, nuclear |
So an offshore construction diver is Classe II Mention A, and saturation sits at Classe III. Training is delivered by INPP in Marseille and by ENS, the École Nationale des Scaphandriers. Prerequisites for Classe II Mention A include being 18 or over, a valid hyperbaric medical less than a year old, a 50 m swim, autonomy at 50 m — and French language proficiency, which is a genuine barrier for non-francophone candidates rather than a formality.
Note ADAS's cut-off for French licences issued after 14 June 2024, which suggests a French regulatory change around that date. If you hold or are pursuing a French certificate and intend to work outside France, verify its current standing before relying on it.
Norway
Two regulators, split by where the water is.
Offshore: Havtil, the Norwegian Ocean Industry Authority. The Activities Regulations require personnel leading or carrying out bell diving or surface-oriented diving to hold a valid certificate, and direct that Chapter 6 of NORSOK U-100N be used for manned underwater operations. Foreign credentials are accepted if they meet the EDTC/IMCA Diving Industry Personnel Competence Standards.
Inshore: Arbeidstilsynet, the Labour Inspection Authority, with its own class system:
| Class | Scope | Minimum training |
|---|---|---|
| Class A | Air, self-contained or surface supplied, straightforward work to 30 m | 7 weeks; 500 minutes and 15 dives at 0–20 m, 150 minutes and 5 dives at 20–30 m |
| Class B | To 50 m, power tools permitted — required for ship husbandry, work near structures, aquaculture, hydraulic and pneumatic tools | 9 weeks building on Class A; 2,200 total diving minutes; at least 5 dives and 150 minutes at 39–50 m |
Legacy certificates: Class R is accepted at Class A level and Classes I, II and III at Class B level. Class S is no longer valid and requires a conversion of four weeks or more. Holders of foreign certificates apply to Arbeidstilsynet for a permit to work inshore.
South Africa
The Department of Employment and Labour's Training Standards for Commercial Diving, dated May 2022, number the classes from high to low — Class I is the top, not the bottom, which trips people up.
| Class | Name | Depth | Minimum training | Prerequisite |
|---|---|---|---|---|
| VI | SCUBA Air, confined water | 8 m | 3 weeks | — |
| V | SCUBA Air, scientific | 20 m | 3 weeks | — |
| IV | Commercial SCUBA Air | 30 m | 3 weeks | Class V |
| III | Surface Supply Air | 30 m | 8 weeks | Class IV |
| II | Offshore Surface Supply Air | 50 m | 12 weeks | Class III |
| IIM | Offshore Surface Supply Mixed Gas | 75 m | add-on | Class II Air |
| I | Saturation Diving | unlimited | per IDRCF standards | Class II |
Entry requirements include being 18 or over, medical clearance, a VO₂ max of 40 mL·kg⁻¹·min⁻¹, English literacy (IELTS 6.5 or equivalent for non-native speakers), numeracy and water competence.
Brazil, India and the rest
Brazil regulates commercial diving through the Navy's Directorate of Ports and Coasts under the NORMAM series. Brazil is not on IMCA's recognised list, so Brazilian divers working on international contracts generally also hold a certificate from a recognised authority.
India has no national commercial diver certification scheme that we could verify, and does not appear on IMCA's list. Indian offshore divers typically hold HSE, ADAS or DCBC certificates obtained abroad. We are flagging this rather than asserting it: if you know of a current Indian scheme, we would rather correct the page than leave it wrong.
Netherlands (NDC-CI), New Zealand (WorkSafe), Sweden and Singapore (DCA, inland and inshore only) complete the picture of named regimes.
The schemes side by side
| Regime | Entry level | Offshore air level | Mixed gas | Saturation | IMCA-recognised |
|---|---|---|---|---|---|
| UK (HSE) | Professional SCUBA | Surface Supplied + Top-Up | — | Closed Bell | Yes |
| Australia (ADAS) | Part 1 | Part 3 (50 m) | Part 3 + SSMG (75 m) | Part 4 (300 m) | Yes |
| Canada (DCBC) | Occupational SCUBA | Unrestricted SS (50 m) | SS Mixed Gas (70 m) | Closed Bell (>70 m) | Yes |
| USA (ADCI) | Entry Level Tender/Diver | Air Diver | Mixed-Gas Diver | Bell/SAT Diver | Yes, with the endorsement caveat |
| South Africa | Class IV | Class II (50 m) | Class IIM (75 m) | Class I | Yes |
| France (CAH) | Classe I | Classe II Mention A | — | Classe III | Via HSE approved list; ADAS only pre-June 2024 |
| Norway | Class A (inshore) | Class B (inshore) / Havtil offshore | — | Saturation class certificate | Yes (Havtil) |
| Brazil | NORMAM series, Navy DPC | No | |||
| India | No national scheme identified | No | |||
| Singapore | DCA | Inland/inshore only | |||
Reciprocity: what works where
Written bluntly, because this is where people lose money.
- The operative filter for offshore work is not "is it a real qualification" but "is it on IMCA's recognised list". Everything else is out, however legitimate it is domestically.
- Inland and inshore certificates are not recognised for offshore diving. IMCA says so explicitly. Singapore's scheme is inland and inshore only.
- In the UK North Sea, HSE Surface Supplied alone is not enough. The Top-Up is what covers wet bell, hot water and offshore standby work, and providers describe it as a mandatory requirement for offshore oil, gas and renewables projects.
- A US ADCI card is the weakest passport into the North Sea. ADCI is recognised, but the International Endorsement is US-residents-only and ADCI's own page has said none had been issued. Most US-trained divers convert.
- Norway is its own gate. Offshore, Havtil requires competence benchmarked to EDTC/IMCA standards and NORSOK U-100N Chapter 6. Inshore, Arbeidstilsynet Class A or B, with a separate permit application for foreign certificates.
- Recognition expires. ADAS accepts French licences only pre-14 June 2024 and South African ones only pre-30 June 2010. Reciprocity is a snapshot, not a guarantee.
- HSE certificates never expire, but currency does. Contractors judge recency of logged experience, not the date on the paper.
Supervisor and LST certification
These are the certificates IMCA actually issues, and the route is the same shape for both: an approved preparatory course, then logged hours in a trainee or assistant role, then a company recommendation based on offshore performance reports, then a written exam.
Diving supervisor
Two grades: Air Diving Supervisor and Bell Diving Supervisor. A supervisor qualified for air only is not qualified for bell, and bell candidates must pass both exams. Minimum logged hours are specified in IMCA D 013. Exams are sat online through invigilation centres in Aberdeen, London, Perth, Trondheim, Singapore, Cape Town, Dubai and Rio de Janeiro.
One change worth knowing: annual CPD through the IMCA Diving CPD App is now required to keep supervisor certification valid. This is new relative to a lot of the advice circulating online.
Life support technician
Two grades: ALST (assistant) and LST. Same structure — approved course, logged hours recorded in the IMCA Life Support Technician Logbook, company recommendation, written exam. Hour requirements in IMCA D 013; course requirements for ALST in IMCA D 073.
The LST path is worth flagging for anyone who wants to work in saturation without being a diver. It is a real career with its own progression to Life Support Supervisor, it pays £468–£801 a day at UK 2026 contractual minimums, and it does not require hundreds of logged dives.
Who is who: the alphabet soup
| Body | What it is | What it does |
|---|---|---|
| IMCA | International Marine Contractors Association — a trade association | Publishes the offshore diving code and D-series guidance; certifies supervisors and LSTs; recognises national diver schemes. No legal authority anywhere |
| IDRCF | International Diving Regulators and Certifiers Forum | The club of national regulators that underwrites mutual recognition |
| IDSA | International Diving Schools Association | Maintains international diver training standards and a table of equivalence between national schemes |
| DMAC | Diving Medical Advisory Committee | Medical guidance notes, including DMAC 21 (the 28-day rule) and the fitness-to-dive series |
| ADCI | Association of Diving Contractors International — a US industry body | Publishes consensus standards and issues US diver cards |
| ACDE | Association of Commercial Diving Educators | The ANSI/ACDE training standard US schools teach to |
| EDTC | European Diving Technology Committee | Fitness-to-dive and competence standards referenced by several regulators |
| Class societies | DNV, ABS, Lloyd's Register, Bureau Veritas | Certify the saturation system as a piece of engineering — nothing to do with divers |
Converting between schemes
People change regimes — because they move country, because the work moves, or because they trained in the wrong place. Conversion is possible but it is never free, and the routes are specific.
| From → to | Route | Practical note |
|---|---|---|
| Any recognised scheme → UK offshore | HSE Surface Supplied (Top-Up), around 5 days | The cheapest and most common conversion. Roughly £2,600 including VAT at 2026 prices |
| Foreign certificate → Canada | DCBC's formal crossover process | One of the cleanest published conversion routes in the industry |
| Foreign certificate → Norway inshore | Application to Arbeidstilsynet for a permit | Assessed case by case. Norwegian Class S holders need a conversion of four weeks or more to Class A |
| Foreign certificate → Norway offshore | Havtil accepts credentials meeting the EDTC/IMCA competence standards | Benchmarked to competence, not to a named certificate |
| US ADCI → North Sea | In practice, an HSE Top-Up or full HSE conversion | The ADCI/IMCA International Endorsement is US-residents-only and has reportedly not been issued in practice |
| Military → civilian | Scheme-specific crossovers | ADAS recognises RAN pre-March 2012, Australian Army pre-August 2017 and RNZN. IMCA requires training open to all, so military-only schemes are not on its recognised list |
Two general rules. First, convert upward, not sideways: adding the offshore top-up in the regime you want to work in is almost always cheaper than re-qualifying. Second, check the recognition date, because reciprocity has expiry cliffs — ADAS's cut-offs for French and South African licences being the clearest examples.
How to verify a certificate
Whether you are a diver checking that a course will be recognised, or a contractor checking a candidate, the same principle applies: verify with the issuing authority, not with the school.
- HSE publishes the List of Approved Diving Qualifications and a list of recognised Diver Competence Assessment Organisations. It has also published a list of invalidated HSE diver training certificates — the existence of which tells you that fraudulent certificates are a real phenomenon in this trade.
- IMCA operates a diver verification portal and publishes which national authorities it recognises. It is the right place to check whether a given scheme opens offshore work.
- ADCI issues cards with expiry dates and requires dives within the preceding 24 months, so a card alone does not establish currency.
- ADAS, DCBC, Havtil and the South African DoL each maintain their own registers.
For supervisors and life support technicians, IMCA's own certification is verifiable directly with IMCA, and since annual CPD is now required to keep supervisor certification valid, a certificate number is not by itself proof of a current qualification.
Questions
Which certification is best?
The one issued by the regulator of the region you intend to work in. HSE for the UK and Norwegian North Sea, ADAS for Australia and wide international acceptance, ADCI for the US Gulf, DCBC for Canada. There is no globally superior certificate, only the right one for your market.
Does IMCA certify divers?
No. IMCA issues air and bell diving supervisor and life support technician certificates only, and recognises nine national authorities for diver certification. Any claim of "IMCA diver certification" is incorrect.
Can I work in the North Sea with a US ADCI card?
ADCI is on IMCA's recognised list, but in practice most US-trained divers take an HSE Surface Supplied Top-Up or a full conversion first. The ADCI/IMCA International Endorsement is restricted to US residents and ADCI's own page has stated that no endorsed surface-supplied certificates had been issued. Check the current position with IMCA before planning around it.
Do diving certificates expire?
HSE qualifications do not — they are valid indefinitely. ADCI cards are valid five years and require dives within the preceding 24 months. But every regime assesses currency separately: contractors judge you on recent logged experience regardless of what the certificate says.
Is an inshore certificate enough to work offshore?
No, explicitly. This is the most common and most expensive mistake new divers make, and it applies to every regime.
What certification do I need for saturation?
HSE Closed Bell, ADAS Part 4, DCBC Closed Bell Diver, ADCI Bell/SAT Diver, South African Class I, or the French Classe III — depending on your regime. All of them sit behind substantial logged experience requirements, typically 100 dives over 100 hours of bottom time, or 10 bell runs in the US system.
How do I become a diving supervisor?
An IMCA-approved preparatory course, logged trainee supervisor hours to the minimum in IMCA D 013, a company recommendation based on your offshore performance reports, and a written exam at an invigilation centre. Air and bell are separate grades and bell candidates sit both exams. Annual CPD is now required to keep the certificate valid.
Verified September 2026 against HSE's published guidance and List of Approved Diving Qualifications (1 January 2025), IMCA Information Notes 1384, 1385 and 1609 and IMCA's certification pages, ADCI's published requirements and Consensus Standards edition 6.5, ADAS scheme documents, DCBC's certificate list, the South African Training Standards for Commercial Diving (May 2022), Havtil's Activities Regulations and Arbeidstilsynet's certificate classes. Schemes change — verify before you commit money.