The first two steps in getting certified in scuba diving is to make sure that you are a reasonably proficient swimmer and you get medical clearance from your doctor to take up the sport. As for the swimming, you don’t have to master every type of stroke. Scuba certification only requires that you are able to swim about 200 yards using any stroke you want and to be able to float or tread on water for about 10 minutes. If you are in good general health and are comfortable in the water, then you should be able to scuba dive without any problems.
Make sure that the course you are interested in taking as well as its instructor are certified with one of the major scuba diving training agencies. This will ensure that you get proper, safe training for both the technical background knowledge and practical skills required for certification as a scuba diver. You also want to end up with an internationally recognized certification card if you want to go scuba diving at various locations around the world.
Some vacation resorts offer ‘resort’ courses lasting a day or two which offer beginners some very basic training in order to try out scuba diving. These are not certification programs. Full certification programs involve classroom work, exams, practical skills sessions at a pool and usually about four open water dives in the sea (lake or ocean). The duration of the classroom work and pool sessions vary from a very intensive weekend (with advance reading) to once a week over several weeks. The open water dives will usually take two more days. Dive centers located in the tropics also offer basic certification programs that last several days to a week. Although the intensive weekend programs are quite feasible, many feel that basic scuba diving courses spread out over a few weeks will help beginners learn the skills better. Scuba diving does involve new skills and to learn them all during one full weekend may be too much for some people.
As for which scuba diving certification training agency is the best, there isn’t any one recognized organization that is better than another. PADI is the most popular in the world but not necessarily better than NAUI or SSI. NAUI course are often more technical in the classroom than those offered by PADI but both will adequately train you to be a scuba diver. The more important factor would be the individual instructor and your own effort during training/studying. In fact, many scuba diving instructors have certifications from several training agencies.
For people living in the more northern regions, there are a few possible routes to take in order to obtain certification. One can travel down south to the tropics and do the entire basic certification course down there in warm weather. However, this will take up a good portion of a vacation since reading, classroom, pool sessions and open water dives all must be done during that time period.
A second option is to take the entire course including the open water dives back in home territory. This usually offers beginners the most time since courses can be spread out over a few weeks. However, the water up north is not as warm as in the tropics and the scuba diving could be seasonal.