The probability of sea turtles biting you is highly unlikely. They prefer to eat food from the ocean, and not humans. If they do bite, it is most probably because you did something that you shouldn't have been doing in the first place- like hand-feeding them or touching them. They are not known to attack human beings. But if they do, their bites can be painful and can cause injury. After all, they do have strong jaws and sharp beaks that they use to eat hard-shelled organisms.