if its the first time to hold classes, the first thing that they will teach is water familiarization. it's a bonus if your child is comfortable in the water. bert lozada has a program called 'baby and me', and the mother/caregiver should be with the baby in the water. i've had my son's swimming class before he turned 4 years old, and he's in between the toddler class and the regular class.
it's better if his classes are close together so the child does not forget the skills and confidence. my son's classes then were every saturday, so the first 30 minutes was just to 'warm him up' to be comfortable in the water, the last 30 minutes lang yung productive for him, tapos malapit na matapos.
choose the swimming pool that has a roof, for your protection and that of your child.
ps. mas maraming available classes when summer comes, but not so much for kids less than 3 years of age. there's one swimming school pa in san agustin campus. try to search for it. they have a website the last time i checked.