When they come up to surface do not block their way, they need breath like us. Once the sea turtle breathe in they can be in underwater about 2 hours.
Most of time they are sleeping or eating in underwater.
You will be able to see green sea turtle in Hawaii lots.
Sea turtle in Hawaii are totally protected, they know we do not harass them so sometimes sea turtle come up to surface very next to you for breath in air. They may be touchable distance but Please do not bother or touch them.
This Ocean is their home, we are a visitors so respect who lives the Ocean. We do not want to bother as much as we can.
Hawaiian green sea turtle.