L.R.
The Villages at Kapolei has swim classes. I'm not sure what times or ages, but I found a link and phone number at this site.
http://www.villagesofkapolei.com/recreati.htm
We took our child to All-Aquatics, which has weekend classes, but that's located in Foster Village by the Stadium. I think they're $80 for 8- 30 minute classes. I think their web site is http://www.allaquatics.org/.
Mililani Recreation Centers used to offer swim lessons as well.
Good luck.