Surely seems to be that
http://www.padi.com is a quite a reputed one for diving certification.
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.