How to choose a dive centre

The short answer

DAN suggests checking whether an operator has an affiliation with a reputable training agency, how often it services its rental equipment, and whether its oxygen units are maintained and available at every dive site. It also suggests asking what ongoing staff training or emergency drills the centre runs.¹

Much of the rest comes from watching and asking on the day. DAN's Alert Diver magazine advises asking the staff questions and paying attention both to what they say and to how they say it.²

Standards and agency affiliation

ISO 24803:2017 is an international standard that sets requirements for service providers in recreational scuba diving. Its scope covers introductory dives, snorkelling excursions, training, guided diving for qualified divers and equipment rental; it does not apply to freediving. A centre that says it meets this standard is claiming to follow a published, external set of requirements, and you can ask how that is checked.³

Training agencies such as SSI publish standards for their courses. DAN suggests checking whether a centre has an affiliation with a reputable training agency.¹

Instructor-to-student ratios

Agencies set maximum ratios for training dives. As an example, SSI's Open Water Diver standards (in a version archived in October 2025) give a ratio of 8 students to 1 instructor for students aged 15 and over, rising to 10:2 with one certified assistant and 12:3 with two. For students aged 10 to 14 the ratio is 4:1.⁴

The figures above come from one agency's standard for one course, so ask the centre which standard it follows and how many students will be in your group.⁴

Group size on guided dives

For fun dives, group size is partly a matter of preference. DAN notes that some divers want a simple, intimate experience while some centres run large-group dives, and suggests deciding which suits you before you choose.¹

Emergency oxygen, first aid and plans

Alert Diver says a dive boat should carry a first aid kit, an oxygen unit, a radio and have non-skid decks. DAN also asks whether oxygen units are regularly maintained and readily available at every dive site, not only back at the shop.^1,2

DAN advises operators to create emergency action plans for all aspects of their operations. As a diver, you should understand what will happen in case of an emergency in the water, and how the crew accounts for every diver; Alert Diver says there must be a physical count.^2,5

Equipment and air

Ask how often the centre services its rental equipment, and how often it tests its gas and services its compressors. When you see the gear, Alert Diver suggests looking for anything old, unclean, in obvious disrepair or badly worn, and asking whether the centre can handle repairs.^1,2

Briefings

According to Alert Diver, the captain should tell you where all the safety equipment is during the boat safety briefing. The divemaster, who should be certified, should then give a thorough dive briefing.²

Boats and local rules

Vessel rules depend on the country. In the United States, for example, a 2019 Alert Diver article notes that vessels carrying more than six passengers for hire from a US port must have a US Coast Guard inspection certificate, and that captains carrying passengers for hire within the US must be licensed by the Coast Guard; smaller vessels and those operating from ports outside the US are subject to different regulations.²

Environmental practices

Green Fins is a Reef-World Foundation initiative, and Reef-World works in partnership with the UN Environment Programme. Dive centres in active Green Fins locations join by signing a membership form and pledging to follow the Green Fins Code of Conduct, after which the Green Fins team arranges a first assessment; centres elsewhere can become Active Digital Members instead.⁶

The Green Fins website has a find-a-member option, and encourages divers to choose a member for their next trip.⁷

Before you go

• Check the centre's training agency affiliation and whether it claims to meet ISO 24803.^1,3
• Ask which ratio standard applies to your course and how big your group will be.^1,4
• Ask whether oxygen and a first aid kit are on the boat at every dive site.^1,2
• Ask how often rental gear is serviced and the compressor and gas are tested.¹
• Ask about staff emergency training and drills, and how divers are counted back on board.^1,2
• Expect a boat safety briefing and a thorough dive briefing from a certified divemaster.²
• If reef impact matters to you, you can check whether a centre is a Green Fins member using the Green Fins website's find-a-member option.⁷