I must agree with several of the posts here. I consider myself an excellent swimmer as I could swim since I was 18 months old, was on the swim team in high school, and a lifeguard instructor in college. As a diver I think good swimming skills (notice I didn't say being a strong swimmer) will pay dividends. Most diving accidents happen at the surface and may require a rather lengthy swim back to the boat/shore. Also, if a buddy is having problems, you may have to drag their tired carcass back to the boat or shore. The COMFORT level gained from possessing good swimming skills will make you less prone to panic underwater, especially if you have difficulty in the ditch-and-donn or regulator recovery portions of your pool sessions/checkout dives. Having skin-dived for the past 20+ years there have been a few times where I have bumped my mask off while looking under a coral head for lobster. Not panicing when a certain discomfort arises is THE key to your survival. Panicing will only cause little problems to turn into big ones. By being comfortable in the water, you will remain rational when faced with a delima instead of panicing and thinking your only option is to become a surface rocket. There are only three people I completely trust underwater, my brother (Firebrand), my instructor (ScubaPolly), and myself. If I dive with anyone other than the first two, the only person I know I can totally depend on for my very survival is myself. Moral of the story: be comfortable and demonstrate good swimming skills, your dive buddies will greatly appreciate it.