My children both started swimming lessons with Linda Riggins Swimming when they were two years old. (She has parent-tot classes but I opted to wait until they were old enough to be in the pool by themselves!) Her organization has been around for a long time; at least 20+ years. She teaches some classes and also has instructors that have been trained in her method of swim instruction. The children start out with 4 "floaties" and gradually build up their skill level so that they can swim without any "floaties". For the novice swimmers, the classes are 1/2 hour and have a maximum of four swimmers per class. (The older children are in an hour-long class - I'm not sure what the maximum number of swimmers in those classes are although I usually see 5 children in them). I enjoy this program and like the fact that the children can learn at their own pace.