Continuity mistake: When Dan walks down to a podium and looks over to see the dolphin knocking at the gate, the tee-shirt he is wearing changes from being plain white with a tag badge on his left, to a white shirt with a large blue stripe across it, with a tag badge being on the right. (00:08:20)
Continuity mistake: When two divers emerge from the water, one pulls their goggles up onto their forehead and the other pulls his goggles down to round his neck. Then the divers and Mike start talking about 'no overtime', and between shots the goggles around the divers neck vanish. (00:07:30)
Continuity mistake: When Mike is in the water doing the welding on the tunnel patch he is wearing a full face mask with the rebreather attached at middle, but when he and Kay are swimming away and go into the door back to the control room after being chased by Jaws, he is wearing just a regular snorkel mask with the rebreather in his mouth.
Continuity mistake: The small shark shrinks a lot when it's brought into the enclosure. If it were its original size, it would have stuck halfway out of the tank.