We took Sebastian to his first swim class. He was almost 8 months old at the time. It was a Parent and Me swim class.
The pool was super warm: over 80 degrees. Since babies can’t generate much body heat, all the kiddie pools are super warm.
The class was mostly splashing, encouraging them to kick, putting them on their back and stomach, and submerging their mouths.
Maybe subsequent classes will submerge them fully. Sebastian seemed to enjoy it.