Visible crew/equipment: When the man is in front of Brody talking to him on the beach the film crew are reflected in Brody's glasses.
Continuity mistake: On the Fourth of July, Sean (the youngest Brody kid) is wearing a white t-shirt with orange around the collar, and green shorts. But after Michael goes into shock and Sean is seen crying, he's suddenly wearing darker shorts and a plain white shirt with no orange. Later at the hospital, he has his orange and white shirt and green shorts on again. (01:01:55)
Factual error: Shooting an oxygen tank (or even an air tank) would not cause it to explode, rather the tank would just empty quickly, but it wouldn't blow up, no matter where the bullet hit.
Factual error: When the woman is yelling that the shark is in the pond, it shows the shark's dorsal fin and tail fin sticking out of the water. The tail fin is moving straight. If the shark needs its tail to swim, wouldn't the tail fin be moving side to side? (01:01:00)
Visible crew/equipment: After hoisting up the damaged cage, when Quint walks over to stand beside Brody in the close-up the reflection of a male crew member's head is visible in the window, behind the ladder, until Brody lets go of the line. The crew's moving shadow is also visible under the cabin window, just after Quint passes it. (01:56:40)
Continuity mistake: After Brody throws down the pump, the shark causes the boat to tip. In the following close-up of Quint's hand, the black and red painted gauge panel behind the wheel is visible. The peeled paint, or lack of, on the ledge going round the bridge deck, and on the steering and throttle controls panel, differs greatly in most of the shots of the bridge deck. (01:41:05 - 01:46:40)
Continuity mistake: When the barrel pops up at the stern of Orca, Hooper grabs the boat hook and reaches for the barrel. In the side shot the barrel faces Hooper's right and the homing device is at the top, in the back shot the homing device is gone and in the third front shot the barrel faces Hooper's left. (01:37:10)
Continuity mistake: When the shark enters the Estuary, he passes Sean playing on the sand. After the attack Michael is pulled ashore and there is a close-up of Sean crying. Behind Sean the orange and white stripe cabanas are visible. However, there are no cabanas at the shores of the pond; these cabanas are located at the main beach area. The footage of Sean, with the cabanas behind him, is from the earlier scene of Alex's attack. (01:02:00 - 01:03:30)
Continuity mistake: When the 'shark fin' (boys playing a trick) approaches a woman she shouts, "My God!" and turns to swim towards the family with three children on a yellow raft, surrounded by other swimmers. In the next shot of a man's reaction, he too swims towards the very same family, but this time the children are in different order and no others surround them. (00:59:10)
Continuity mistake: When the two old fishermen are fishing for the shark from the pier, the shark takes the bait and you can see the chain getting pulled into the sea. In the next shot you can still hear the chain being pulled into the sea but if you look on the pier, you can't see any chain being dragged in and the wooden post that the chain is secured to changes into a different position. (00:25:20)
Continuity mistake: In the scene where the shark eats the guy in the red boat in the pond, Brody grabs a red blanket and goes for a brown blanket after exclaiming, "He's in shock," in reference to his son's close encounter with the shark. In the next shot, his wife is laying down blue and brown blankets over Michael. (01:06:05)
Revealing mistake: After Hooper delays Quint's shot of the very first harpoon into the shark, he finally shoots and hits the right side of the shark's dorsal fin. Problem is that in this particular shot there is another harpoon already on the left side of the shark's dorsal fin! This is the exact same shot seen later in the film, after Quint shouts, "Run him down Hooper!" (01:24:50 - 01:41:00)
Continuity mistake: There are long poles and large hooks clipped to both the starboard and port side of Orca. In quite a few shots all three poles are gone from either side, and in other shots the amount of poles and hooks and their positions change repeatedly over and over again, in consecutive shots throughout their hunt! (01:41:15)