The Brief Kalin DiRoma enrolled her children in Infant Swimming Resource (ISR) classes to ensure their safety in the pool. ISR swim instructor Laura Castle has spent 14 years teaching self-rescue skills to children from six months to six years old. That is why DiRoma started looking for swimming lessons for her two girls and eventually decided on (ISR), or Infant Swimming Resource classes. Castle has been teaching ISR swim classes for 14 years. "I do think it's the most important skill you can give to your child," Castle said.