What did you do for swimming lessons?

This has been a source of frustration for me. Oldest will be 4 by summer. They did 9 days of lessons with the city when they were 1.5. Then again last summer. They have been utterly useless as they are ran by children (high schoolers) with no supervision.

They also did a week of 1 on 1 lessons, but also not sure how much they gained from that. They are very experienced in the water and jump in, float with floaties, etc.

They just can't swim yet and I don't know what type of lessons we should be doing. ISR is $1,000 apparently.

What did you do for swimming lessons?