Getting started in scuba diving.

The route the agencies describe

1. Optionally, a try dive. Many agencies offer a short introductory dive with no certification. See try diving.
2. An agency and a course. The main agencies and their entry-level cards are on training agencies and certification levels.
3. Medical screening. Where the screening form calls for it, a physician decides whether the person may dive. See medical screening.
4. The course. Theory, pool or confined water sessions, then open water dives, as described below.
5. The card. Each card carries the limits its agency publishes. See depth limits by certification.

What the entry-level courses contain

This is a summary of each course's parts as the agency describes them. It says nothing about the skills taught, which are for an instructor to teach.

How long it takes

PADI's own sources give different figures. Its current course page says Open Water Diver can be completed in as little as 2 to 4 days, while its 2018 blog says about 4 to 7 days. The two were published at different times. GUE gives 5 to 6 days for its course, and SSI recommends 16 to 32 hours of training.

What is asked of you before you start

PADI lists being able to swim and being medically fit for diving, with a swim and float assessment, according to a search summary of its course page. SSI's standard requires a water fitness evaluation before open water training dives. BSAC requires all diving members to meet its medical requirements before any training or diving. GUE's prerequisites include being a non-smoker, being able to swim, being physically and mentally fit, and holding a physician's prior written authorisation for prescription drugs or for conditions that may pose a diving risk.

Minimum ages for the first course

Each figure is the agency's own statement for its entry-level course. PADI's figures are from its course page (seen as a search summary) and its blog of 27 February 2024, and SSI's from its standard archived 14 October 2025; the NAUI, BSAC, SDI and GUE pages carry no date (we read them in October 2026). Where an agency's pages disagree, both figures are on depth limits by certification.

• PADI Open Water Diver: 10; ages 10 to 14 certify as Junior Open Water Divers.
• SSI Open Water Diver: 10; under-15s certify as Junior Open Water Divers.
• NAUI Scuba Diver (supervised): 15 by the water phase, with junior certification for ages 10 to 14.
• BSAC Ocean Diver: from 12.
• SDI Junior Open Water Scuba Diver: from 10 with parental consent, upgrading at 15.
• GUE Open Water Diver: 12 on the course page, 14 on GUE's recreational curriculum page.

After the course

The card records that the course was completed. PADI's blog (updated 25 November 2024) says divers must have proof of certification and recommends carrying both a physical card and an eCard, because non-PADI centres and most liveaboards generally cannot look a PADI diver up online. Wikipedia (secondary) describes the logbook as the record of a diver's actual experience, separate from the card. Further training, from advanced courses to specialities, is set out on certification levels and specialty certifications.

On equipment, the section starts with masks, snorkels and fins, and renting or owning sets out the choice between the two.