Mixed Gas Diving Supervisor Pass Rate 2026: What the Data Shows

The Pass Rate Question: What Is Actually Known

Search for the Mixed Gas Diving Supervisor pass rate and you will find confident-sounding numbers on forums, training-provider brochures, and aggregator sites. Here is the uncomfortable truth: the Association of Diving Contractors International (ADCI) does not publish a pass rate for its HeO2/mixed-gas supervisor examination, and no independently verified figure exists in the sources we can cite. This article will not invent one.

That might sound like a disappointing answer to a data-focused headline, but understanding why the number is missing, and what the available evidence does show, is far more useful to a working diver planning a supervisor career. The structure of the credential itself tells you a great deal about how hard it is to earn, even without a headline percentage.

Why No Official Figure Exists for This Credential

Large, high-volume certification programs often publish pass-rate summaries because they test tens of thousands of candidates annually. The ADCI mixed-gas supervisor credential works differently. It sits at the top of a narrow professional pipeline: a candidate must already be a working commercial diver, already qualified as an air-diving supervisor, and already logged substantial mixed-gas experience before the exam is even relevant.

Several structural reasons explain the absence of a public figure:

• Small, self-selected candidate pool. Only experienced divers who have cleared the experience gates attempt the exam, so the population is far from a random sample.
• Industry-standards purpose. The exam exists to verify competence against the ADCI International Consensus Standards, not to serve as a marketed, volume-driven test product.
• Employer-driven demand. Candidates typically sit the exam because an employer is vetting and assigning them in writing, not because they are shopping for a credential.

For a broader look at how difficult candidates report finding the exam, see our guide on how hard the Mixed Gas Diving Supervisor exam is. For the scoring side of the question, our article on the Mixed Gas Diving Supervisor passing score explains what can and cannot be stated about the cut line.

The Real Gatekeeper: Prerequisites Before You Sit the Exam

If you want a proxy for difficulty, look at who is allowed through the door. According to the ADCI standards, the credential requires all of the following, not just a passing exam result:

Because candidates arrive with hundreds of field days and a documented apprenticeship under a working supervisor, the effective "failure risk" is concentrated in knowledge of the written standards, not in raw diving ability. Many experienced divers know how to do things on the job but have never had to cite the governing section of the standards from memory. That gap is where preparation matters. Our Mixed Gas Diving Supervisor requirements guide walks through each prerequisite in more detail.

How to Spot Unreliable Pass-Rate Claims

Because this topic has an information vacuum, it attracts filler. When you encounter a pass-rate figure for this credential, run it through a short sanity check:

1. Does it name a source? A real figure should cite ADCI or a documented dataset. Vague phrases like "industry estimates" are a red flag.
2. Is it confusing credentials? Other diving and non-diving certifications share similar names or acronyms. ADC-UK and IMCA examinations are different programs with different bodies and rules, and statistics from them do not transfer here.
3. Is it precise without explanation? A figure like "73.4%" with no methodology, cohort, or date is almost certainly fabricated or borrowed.
4. Is it selling something? Treat pass-rate claims attached to a paid course as marketing until proven otherwise.

On this site, we deliberately avoid presenting numbers we cannot substantiate. If you want the full picture on cost and scheduling instead, our pages on certification cost and exam dates cover what is documented.

Where Candidates Are Most Likely to Struggle

Without official statistics, the most honest guidance comes from the structure of the source material. The exam is based on the ADCI International Consensus Standards, and our preparation is built around edition 6.5 (the issuer's homepage currently links a PDF with a July 27, 2025 revision filename). The standards are dense, procedural, and cross-referenced. Experienced divers tend to stumble in predictable ways:

• Treating field habit as standard. Practices that are common on your usual vessel or site may differ from what the standards require. The exam tests the standard, not local custom.
• Underestimating the supervisor responsibility list. Section 3.6 is long and granular. Missing a single item, such as post-dive observation for symptoms or verification of logs, can matter.
• Blurring surface-supplied mixed-gas with saturation. The standards contain saturation-specific provisions. Candidates preparing for a surface-supplied HeO2 credential should apply the mixed-gas context and not assume saturation rules apply universally.
• Neglecting equipment minutiae. Compressor and air-purity requirements, manifold and regulator details, and gauge and timekeeping rules reward careful reading.
• Weak emergency recall. Loss of breathing media or communications, trapped or injured divers, umbilical damage, and fire all have specific expected responses.

The Five Study Groupings and What Each Demands

The groupings below map directly to published sections of the ADCI standards. They are an editorial study map, not official exam domains or weights. For a longer treatment, see our complete guide to all five content areas.

Fees and Registration Mechanics

On the money side, the facts we can state are limited but concrete. The issuer's current certification page lists an online exam as required and shows $275 for the supervisor card category. We cannot describe that figure as an independently verified, exam-only fee, so treat it as the card-category price listed by the issuer and confirm current details directly before budgeting.

Remember that the card is only one piece of the process. The mode-specific supervisor card sits alongside the experience prerequisites, medical fitness, and CPR/first aid requirements. A full breakdown of what you may spend across the whole path is in our certification cost guide, and our exam dates article covers scheduling considerations.

Who Hires Certified Mixed-Gas Supervisors

The credential is employer-centered. Under the standards, employers vet candidates and issue written assignments, so the demand for certified supervisors comes from diving contractors running surface-supplied mixed-gas operations. In practice that points toward commercial and offshore diving contractors and the project owners who require ADCI-aligned operations. Because we do not have verified salary or placement statistics, we will not quote earnings here; our salary guide and jobs overview discuss the career landscape qualitatively, and our ROI analysis helps you weigh the investment against your own situation.

A Domain-Ordered Preparation Sequence

Since you cannot target a weighted blueprint, a sensible approach is to sequence your reading by dependency: responsibilities first, because everything else hangs from them. Here is one way to order a roughly four-week plan around the standards sections.

Scheduling emergencies last is deliberate: those scenarios draw on duties, equipment, and operations knowledge all at once, so they work well as a capstone and review. For a fuller plan, see our study guide for passing on your first attempt, and keep our one-page cheat sheet handy for last-minute review. When you are ready to test yourself against realistic questions, try the Mixed Gas Diving Supervisor practice tests.

Frequently Asked Questions

The honest conclusion about the Mixed Gas Diving Supervisor pass rate is that the number you are looking for does not exist in verifiable form. What does exist is a clear, published standards base and a rigorous set of prerequisites. Spend your energy mastering the source material, and use our certification overview to confirm each step of the path.