My Personal favorite was medina lake, it is a half hour from San Antonio. If you dive from the marina on lake medina you can do a wall dive. There is an underwater muesem consisting of a speed boat, a jon boat, a lawn tractor, plymouth horizon, a walk around style boat and you can even follow the rails that they used for mining. I believe it was a rock quarry before it was dammed. The jon boat is in shallow water and there is plenty of fish around it. The fish are pretty good size there: Bas 5 - 10 lbs, cats 5 - 10lbs and some descent sized pan fish. The vis is around 10 ft and depths reach 135'. after about 70' the vis is horrible. There is also canyon lake over there on the east side but I never dove it. Duggan diving uses canyon lake for training and they can give you water conditions. Dive masters of San Antonio uses medina lake and they should be able to give current conditions. As mentioned in others posts their is a fee. It used to be $5 per carload.