Scuba Certification Guide
Explore scuba certification stages and training agencies in a practical, guidebook-style overview.
How to use this guide
The name of a training agency is only one part of choosing a scuba course. Start with the kind of diving you want to do and the training environment where you can learn and practice well.
This guide follows the path from introductory experiences to recreational diving, rescue training and professional courses before comparing agency course names.
Similar course names do not always represent exactly the same qualification. Before enrolling, confirm the current requirements with the agency and the dive center.
Already considering a professional path?
Dive leader, divemaster, and instructor training have different entry requirements from recreational certifications.
Where are you in your diving journey?
Start with the section that matches your current stage instead of trying to memorize every certification name at once.
| Stage | Start by checking |
|---|---|
| Getting started | The difference between an experience and an entry-level course |
| Continuing education | The purpose and prerequisites of advanced and specialty courses |
| Safety and rescue | What rescue training covers and what experience it requires |
| Professional path | Separate entry requirements for divemaster and instructor training |
Recreational certification stages
The courses below are placed side by side by purpose, not presented as exact equivalents.
| Stage | PADI | SSI | NAUI | SDI | RAID | CMAS |
|---|---|---|---|---|---|---|
| Entry-level | Open Water Diver | Open Water Diver | Open Water Scuba Diver | Open Water Scuba Diver | Open Water 20 | One Star Diver |
| Continuing education | Advanced Open Water Diver | Advanced Adventurer¹ | Advanced Open Water Scuba Diver | Advanced Adventure Diver | Advanced 35 | Two Star Diver |
| Rescue and safety | Rescue Diver | Diver Stress & Rescue | Rescue Scuba Diver | Rescue Diver | Rescue | Rescue Diver |
| Experience and specialties | Specialty / Master Scuba Diver | Specialty / Master Diver | Specialty / Master Scuba Diver | Specialty / Master Scuba Diver | Specialty / Master Rescue | Specialty / Three Star path |
Before reading the agency comparison
¹ SSI Advanced Adventurer is a program built around five adventure dives and should not be confused with SSI's Advanced Open Water Diver recognition rating.
The comparison is not a ranking of training agencies. Courses at a similar stage may differ in learning content, in-water practice, recognition systems and progression paths.
The comparison will place course names side by side, but it will not force a match where no direct counterpart exists. Treat depth, duration and age requirements as context-dependent information rather than guaranteed values.
What to notice about each agency
PADI
PADI offers a familiar recreational path from Open Water Diver to Advanced Open Water Diver and Rescue Diver. Read the advanced course as a way to gain experience and sample specialties rather than as a simple status label.
SSI
Advanced Adventurer is a program built around five adventure dives. It is distinct from SSI's Advanced Open Water Diver recognition rating, so confirm which program and card a center provides.
NAUI
NAUI presents step-by-step courses such as Open Water Scuba Diver, Advanced Open Water Scuba Diver and Rescue Scuba Diver, with safety and professional pathways to explore alongside them.
SDI
Alongside Open Water Scuba Diver and Rescue Diver, SDI uses both Advanced Adventure and Advanced Diver programs with different purposes. Check the required specialties and logged experience, not only the course name.
RAID
RAID uses course names such as Open Water 20, Advanced 35 and Rescue to describe progression and experience. Confirm the current standards and how the local center delivers the course.
CMAS
CMAS expresses its training structure through One Star, Two Star and Three Star levels. Read the international standards together with the way the relevant national federation operates.
Frequently asked questions
Can I enroll in the next course with a certification from another agency?
Often, but it is not an automatic one-to-one conversion. The dive center may review your previous certification, logbook, recent experience and specialty prerequisites before confirming the available next course.
Does every course called Advanced mean the same thing?
No. Some programs introduce several environments through supervised experience, while others lead to a distinct recognition rating or require additional prerequisites. Check the training content and the credential issued, not only the course name.
Do scuba certifications expire?
Certification validity, active status, recent-experience expectations and refresher requirements vary by agency and center. If you have not dived for a long time, ask what refresher training is recommended before booking.
Should I choose a course by its maximum depth?
Not by itself. A maximum depth may refer to a training limit or a recommended range, and it does not describe every skill needed for that environment. Prioritize enough practice in buoyancy, gas management and emergency procedures.
What should I check if I am considering a professional path?
Professional courses have separate entry requirements such as logged dives, rescue, first aid and instructor assessments. The professional track will be covered on a separate page.
Questions to ask before booking
- Is this an introductory experience or a certification course?
- How much theory, confined-water practice and open-water training are included?
- Are equipment rental, learning materials, certification and additional training included?
- What is the instructor-to-student ratio?
- Does the course support the kind of diving and next training step I want?
Compare the actual learning and practice included, as well as whether you feel comfortable asking questions—not only the price.
Prepare for your next conversation
Talk with a dive center about the training you are considering and compare the path that fits your current stage.