Many people have heard before that infants know how to hold their breath when submerged. There is some evidence to support the idea that infants hold their breath under water. However, the reflex does not appear to be that strong and is not very reliable, especially in older babies. In addition, other reactions can compete with this breath holding reflex, including the startle reflex. So if you suddenly submerge a baby under the water, they may actually do like this with their mouth open and actually suck in and cough on water. Fortunately, all babies can be safely prepared for under water swimming by using a signal, and I'm going to demonstrate. You take your child in your arms, and you say, "Name, ready, go," model taking a breath, and then dump a little water over their face. You follow with a reward. So, "Dolly, ready, go." (breath) Dump a little water, and then right away you want to bring something fun. If you go slowly enough and with just a tiny bit of water, only increasing water as your child becomes comfortable, they will begin to expect this as a fun routine. When your child shows knowledge that the water is coming by tightly closing their eyes and even lowering their head, they'll be ready for under water submersions.