Continuity mistake: When Fischer was quickly getting his clothes on to get to base after he spent the first night with his girlfriend, he put a shirt on, and then in the next shot he didn't have a shirt on and he put the same shirt on again.
Continuity mistake: When Kevin Costner arrives at the diving school, there is a board on the wall containing a list of base records where Costner's character owns all bar one. In a later scene at the swimming pool, Costner brings a board which lists the base records where Costner now owns them all.
Continuity mistake: When the new recruit and the teacher go into the water together, for a rescue, at one stage, one of them is going straight ahead to the cave, like he's supposed to, but the other one is heading right, which is completely wrong; but then, somehow, they're together again.