How do i make my character breathe again at surface of water

i have a oxygen system just cant make it start breathing while treading waters surface

What if you had a sphere collision around the character’s head (or even a small box where the mouth is) and perform onComponentEndOverlap against the water? Would that work?

Depending on the animation, he would likely need to have the box a tad above the head to ensure it would always read as ‘notOverlapping’ once the surface of the water is breached. Great suggestion and likely the easiest route by adding the box component to the player blueprint!