So, you've picked where to learn to dive, and you're asking around town to find the right school. There's more factors than cost to consider – here's a few points to look for.
Small Class Sizes
PADI, the world's most popular diving certification agency, allows one instructor to teach as many as eight students. Ideally, though, you'll want only a couple of students in the class – or additional assistants in the water to help you practise skills. You'll learn more if you're not waiting for seven people to complete each skill in the water before you have your turn, and it's safer.
Particularly with junior divers (children as young as 10 can learn to dive) but also for petite women and larger guys, equipment fit can be key to learning to dive. If you're a non-standard size, try on a wetsuit and investigate BCD (inflatable diving jacket) sizing before you commit to the course. A wetsuit should fit snugly, with no baggy bits, but not squeeze: a fully inflated BCD should feel snug on the shoulders and mid-section, and allow easy access to your weightbelt. All dive stores carry BCDs in S, M and L sizes. Petite women might need XS or XXS, slight children might need XXXS, while bigger guys might need an XL or even an XXL.
Good Safety Standards
Is the gear checked regularly? Is emergency oxygen available on shore or on the boat? Most importantly, will a store let you dive outside your training? Any shop that will take a new diver into a deep, dark wreck or an open site with washing machine currents is not a safe place to learn.
Minimal Sales Pressure
Learning to dive is a lifelong process – even divers with thousands of dives continue to learn. So it's generally best to bank a few “fun” (non-training) dives to get more of a handle on key skills like buoyancy and air management without an instructor hovering beside you before you move onto a new course. If a store is pushing you to move from Open Water to Advanced Open Water to Rescue Diver in a couple of weeks, they're doing it wrong.
The Right Instructor
Not all instructors are created equal. Scuba instructors got into teaching because they love diving, and some loathe teaching with a passion. Chat to your instructor before you commit, and try and get a feel for their personality and teaching style.
Reasonable Course Length
Some shops will try and get you through an Open Water course in as little as two days. Initial courses include not only practical skills in the water but an entire book's worth of learning: unless you've started studying online already, look for a course that runs for longer.
A Good Course
The majority of divers around the world train with either PADI or SSI. Some consider that CMAS and NAUI, cards that are also accepted worldwide, provide more rigorous, in-depth training, including self-rescue skills: if the store you decide on offers alternatives to PADI and SSI, have a chat to the instructor about what they recommend.