There are many benefits of baby swimming even if it is a slightly daunting experience for most parents trying it for the first time.
For the most part there is nothing to worry about. Infants can start swimming from birth. Be aware though that babies can chill easily, so consider the temperature of the pool.
Many swimming lessons start from around three months, however, you are encouraged to check with your health visitor before enrolling.
*quoted from Swimming.org.com