What certification means in practice
A diving certification records completion of a particular training programme. It should be identified by the agency and course name. Read the official course description and discuss suitability with the training provider.
An example to think through
A person says they have “done a dive before”. That could describe an introductory experience or a completed course. Asking for the exact programme name avoids building a booking around the wrong assumption.
A common misunderstanding
A participation experience and a completed certification course are not interchangeable descriptions.
Underlying concept: PADI — Become a Certified Scuba Diver FAQs. The example is an original YouDive study prompt, not a reported dive.