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What you should know before getting into commercial diving

By Arthur More · professional saturation diver · 18 August 2026

Published 15 July 2026 · 11 min read · 2,275 words

In brief

Before enrolling in commercial diving you need a current medical certificate, a solid base level of fitness, tolerance for hard manual work and realistic expectations: months away from home, spells without a contract and an uneven first few years. The course is expensive and doesn't guarantee work; what gets you hired is the trade skills you bring.

Most people who leave commercial diving don't do it because they couldn't dive. They leave because the job turned out to be different from what they'd imagined, because they couldn't handle the lifestyle, or because they ran out of money before the first decent contract came along. Almost all of that can be anticipated before you pay for the course.

What follows isn't a motivational list. It's an honest rundown of what you should have sorted, or at least coldly assessed, before committing several thousand euros and a few months of your life.

What the course assumes you already have

A commercial diving school teaches you procedures, equipment and standards. It doesn't teach you to handle tools, it won't get you fit, and it won't build the mindset to spend two months on a barge. The programmes are packed and the pace is fast: if you're starting from zero in several of these areas, you'll spend your energy surviving the course instead of getting the most out of it.

The practical result is that two students with the same qualification come out with very different market value. One brings workshop welding, sling handling and five years on site behind him. The other brings a card. The employer notices the difference in the first week.

Before anything else, it's worth understanding the full pathway and what steps come after the initial course. The guide on how to become a commercial diver lays out that sequence.

Medical fitness: the filter that isn't negotiable

The professional diving medical is a legal requirement, renewed annually in most jurisdictions, and it's signed by a doctor with specific training in diving and hyperbaric medicine. It isn't the sports certificate from your local health centre, and you don't pass it by insisting.

Get it done before you enrol. It's a small outlay that can save you the full cost of the course if something incompatible turns up. That's the logical order, and too many people do it the other way round.

What the medical usually checks

Respiratory function: spirometry, history of asthma, previous pneumothorax or lung disease.
Cardiovascular system: blood pressure, ECG and, depending on age and protocol, a stress test.
Middle and inner ear: ability to equalise, eardrum condition, history of barotrauma.
Central nervous system, with particular attention to a history of epilepsy or loss of consciousness.
General condition: body mass index, diabetes, chronic medication and substance use.

Some conditions rule you out permanently, others only temporarily. If you have doubts about your history, the article on what the commercial diving medical certificate assesses goes into detail. And if something worries you, ask about it at the appointment before you book a place.

Fitness: endurance, not gym looks

Commercial diving doesn't require a competition-level physique, but it does need a solid base. What wears you down isn't a single hard effort but the accumulation: twelve-hour shifts, constantly moving heavy equipment on deck, suits and helmets that add kilos, and days strung together for weeks without a proper rest day.

Cardiorespiratory fitness matters because breathing against resistance while working in a current is demanding. Functional strength in the back, core and grip matters because you'll be handling umbilicals, hydraulic tools and rigging gear. Flexibility and joint health matter because wear on the shoulders, knees and lower back is why many divers leave the water before their time.

If your current fitness level is sedentary, six months of base training before the course will completely change the experience. You don't need a sophisticated plan: consistency, progressive load and looking after your back.

Recreational diving helps, but not in the way you think

Coming from recreational diving brings real advantages: you're comfortable underwater, you know how to equalise, you have the basic reflexes, and you don't panic when water gets into your mask. That takes care of the emotional side of the first helmet dives, which can be tough for someone with no water experience at all.

But that's where it ends. In commercial diving you don't choose where you go in or when you come out, you don't carry self-contained gear on most jobs, you're tethered to an umbilical, you talk over comms to a supervisor who runs the dive, and you go down to work, not to look around. Visibility is usually poor or nil, and a good part of the work is done by feel.

It's also worth dispelling a common idea: hundreds of recreational dives don't give you a hiring advantage. What gets you hired is your ability to produce underwater. If you're coming in with no prior experience of any kind, the route in is described in how to start in commercial diving with no experience.

The trade: what you'll actually be asked to do

This is the part that most separates those who find work quickly. A commercial diver is, above all, a skilled tradesman who also happens to work underwater. The more of a trade you bring from onshore, the sooner you'll be useful and the sooner you'll get called back.

Tools and rigging

Handling hand and hydraulic tools, grinders, torque wrenches, pneumatic hammers. A grounding in rigging and lifting: sling types, shackles, working angles, load estimation, signalling to the crane operator. On deck and underwater, a good part of the time goes into moving and securing heavy things, and getting it wrong is the fast route to an accident.

If you're coming from construction, industrial maintenance, boating or mechanics, you already have a good part of this. If not, a short rigging course or a few months in a workshop are worth more than they seem.

Welding and cutting

Underwater welding is a specialty you take on later, not something you master straight out of the basic course. But arriving already able to weld dry, with a coated electrode and a reasonable technique, puts you ahead. Oxy-arc cutting also comes up in a lot of scopes of work.

Nobody expects you to arrive as a certified welder. But it does make a difference that you understand the process, know how to prepare a joint, and aren't discovering the electric arc for the first time underwater.

Technical English

As soon as you step outside the local market, English stops being optional. Briefings, permits to work, procedures and comms with the supervisor are handled in English across nearly all of the international offshore sector. You don't need to discuss literature: you need to understand an instruction over comms, read a procedure and describe precisely what you're seeing underwater.

It's probably the investment with the best return per hour spent. A competent diver with working English can access a market several times larger than the same diver without it.

Mindset and realistic expectations

This is the part where it pays to be especially honest with yourself, because no amount of training makes up for it. The job means spending long spells away from home, with rotating schedules and forced close quarters. Personal and family relationships feel that rhythm, and not everyone copes well with it.

It's also worth accepting that this is a job with real risk. It's heavily procedure-driven precisely because the consequences of a mistake are serious, and the industry takes safety seriously. But procedural discipline isn't negotiable and allows no shortcuts: if you're someone who improvises, this trade is going to clash with you.

And there's the matter of income. The high figures that circulate belong to divers with years of experience, a specialty and days worked behind them. The first years tend to be uneven, with spells without a contract between projects, and entry-level jobs that pay considerably less than the headline numbers suggest. Before doing any sums, it's worth looking at real ranges by profile and region in how much a diver earns.

The money: course cost and a cushion for afterwards

Entry-level courses vary a lot by country and qualification. In Spain, a shallow-depth professional diving course runs somewhere around 1,600 to 2,100 euros depending on the school and season. In the United Kingdom, an HSE surface-supplied qualification, around five weeks long, sits in the range of several thousand pounds, with accommodation sometimes included. The higher tiers are much more expensive: closed bell training, which qualifies you for saturation, runs into tens of thousands of pounds and requires accredited prior experience.

The common mistake is budgeting only for the course fee. On top of that you need to add the medical, accommodation and travel during training, the safety and survival courses offshore contractors require, basic personal kit and, above all, months of living costs with no income while you look for the first contract.

Fee for the initial course and, later on, for the next qualification tier.
Diving medical, renewed annually.
Accommodation and travel during the weeks of training.
Sea survival and offshore safety courses required by the client.
Personal kit: check what you're expected to bring yourself in the section on equipment.
A financial cushion for the months after the course — that gap is rarely zero.

Comparing schools before deciding is time well spent: the price matters less than whether the qualification is recognised in the market where you want to work. Cross-check the list of schools with the map of certifications before paying anything.

Checklist before you enrol

If you had to boil it all down to a checklist, this would be it. You don't need to have everything sorted, but you should know where you stand on each item.

Professional diving medical done and passed, not assumed.
Physical base built over months, with attention to the back and shoulders.
Some prior water experience, even recreational, so you don't spend the course getting over your fear.
Real hands-on trade skill: tools, rigging, mechanics, welding or construction.
Enough English to understand a procedure and communicate over radio.
An honest conversation with the people around you about long absences and rotating schedules.
A budget that covers the course, extras and several months afterwards with no income.
A target market chosen, and a qualification that matches that market.

The requirements for commercial diving that appear in a school's brochure are the administrative minimum. What determines whether you'll last in the trade is this other list. Once you've reasonably covered it, look at what's being asked for in the job listings in the industry: reading the real requirements of real jobs is the best way to gauge how far you still have to go.

Commercial diving is a good trade for those who fit it, with interesting technical work and a clear progression if you rack up hours and specialise. But it's a bad place to discover along the way that it wasn't for you, because the bill for that decision is paid upfront.

Frequently asked questions

Do I need to be a recreational diver before doing the commercial diving course?

It isn't compulsory at most schools, but it helps. Arriving comfortable underwater lets you spend the course learning procedures and work, rather than managing the anxiety of the first helmet dives. That said, recreational experience doesn't count as a professional credential: what employers value is your ability to produce underwater.

How much does it cost to train as a commercial diver?

It depends on the country and the level. In Spain, a shallow-depth course runs at around 1,600 to 2,100 euros depending on the school and season. Surface-supplied qualifications in the United Kingdom cost considerably more, and closed bell training for saturation runs into tens of thousands of pounds. Budget too for the medical, accommodation, safety courses and months without income.

What level of fitness do you need for commercial diving?

Endurance rather than maximum strength. What wears you down are the long shifts, the constant handling of heavy equipment, and weeks strung together without proper rest. It's worth working on cardiorespiratory fitness, functional strength in the back, core and grip, and joint mobility. If you're coming from a sedentary life, six months of preparation beforehand completely changes how you cope with the course.

Is it essential to know how to weld before starting?

It isn't an entry requirement, but it counts for a lot. Underwater welding is a later specialty; arriving already able to weld dry with a coated electrode and understanding joint preparation puts you ahead of other candidates. The same goes for handling hydraulic tools and having a grounding in rigging and lifting.

How long before I can make a living from this after finishing the course?

Rarely straight away. The usual pattern is stringing together short jobs, spells without a contract, and travelling to be available where there's activity. The first years bring irregular income, and the jump to higher rates comes with accredited experience and specialisation. It's worth planning the start of your career assuming several months without steady earnings.

Published 18 August 2026 · By Arthur More, professional saturation diver

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