When baby has been under for more than 3 seconds and does not have their own breath control, this reflex leads to a redistribution of blood flow ensuring the 'key' organs i.e. the brain and heart, receive a steady supply of oxygen. The 'diving reflex' is perfectly natural and slowly starts to diminish from between 6-9 months of age. Over time this reflex turns into the 'dive response' which ‘free divers’ access to enable them to stay under the water for long periods of time.
We do not actively encourage the use of the dive reflex as it is a survival reflex and can cause panic in the baby.

Although babies have the ability to stay under the water for longer than 3 seconds it doesn’t mean they want to. We aim to teach you as parents how to read your baby’s cues and understand what they are saying to you with their body language and facial expression.