Until the age of 3 y.o. a parent/guardian has to go in the pool with them.
One thing you can do to prepare them is to tip water over their heads to get them used of having a continous flow of water on their heads/faces. I noticed the teachers do that during the babies’ lessons. Although the pools are heated some little ones get cold. To help overcome that you can put rashies over the top of their bathers. You can get one piece ones that do up at the back with a zip for the little ones. One 4 year old I know still wears the one piece for extra warmth because otherwise he sometimes gets cold enough to start going blue. On occasions they have taken him out of the water before the end of the lesson. A lot of the change rooms have showers and toilets / change tables for those still in nappies.

Water safety is is a skill for life.

My son cody been swimming since 9 months old loves it he learning more and more eveeyday and one day will save his life i think all childern should learn to swim helps them learn about not being scared if they fell in water etc they know swim to edge they should make it compulsery by law all kids have to do it

I was the same I booked in early but found he did not progress that much over the younger years so I waited until the younger siblings were 3 before starting them.

reading these stories are great