Continuity mistake: Hooper wears rimless eyeglasses, with the arms either attached at the upper corners of the lenses or at the sides of the lenses. If this didn't happen between shots within the same scenes, it could be presumed that Hooper has two different pairs of glasses and switches between the two, but they do indeed change between shots, such as when Mrs. Kintner slaps Brody, or even later, on the Orca. (00:36:05)
Continuity mistake: Quint embeds his machete into the wood at the side of the boat, but in the following wide shot the machete is gone. Then as Orca starts to move, when Hooper says, "He's chasing us, I don't believe it," the machete is back. When the shark leaps onto the boat the machete is gone again, and then as the shark devours Quint the machete is back for him to grab, so he can valiantly stab the shark. (01:44:30)
Visible crew/equipment: When the fishermen start out on the hunt, Ben Gardner appears in a close-up leaning on the windshield at forward deck, while talking to his boatmate about how stupid some of the others are. In the next wide shot of the boats, Ben's green boat is towards the left of the screen, and a camera operator beside the camera and reflector screen mounted to the bow of Ben's boat, are all visible in front of the forward window where Ben was seen in the previous shot. (00:30:25)
Continuity mistake: When Hooper gets his gear from below, after the explosion in the engine room, he runs to the deck passing Quint using the fire extinguisher. The camera pans from Brody, who stands on the bridge deck, to Hooper right below him. So where exactly is the tall iron ladder that leads up to the bridge deck in this shot? It should be behind Hooper, in front of the window, but it's gone. Don't fret, it's back in the following shots. (01:49:05)
Continuity mistake: During Quint's attack, as the shark's biting down on his legs, Quint's bare hand is grabbing the shark's snout. Subsequent shots show Quint wearing gloves as he's devoured. (01:57:35)
Revealing mistake: Just as Quint finishes scraping his nails on the chalkboard, the camera begins to move in closer when he takes the first bite of the cracker. On the right side of the screen under Harry's chin, Roy Scheider is ducking down while staring at the camera, as it pans toward Robert Shaw, and Roy then lifts his left hand up, cueing Robert's line. (00:20:55)
Revealing mistake: While Quint is in the shark's mouth, the comfy white cushion is visible under his back, protruding from the shark's mouth. (01:57:30)
Continuity mistake: At the scene just after the fake shark scare, the real shark shows up at the pond area of the beach. As the lifeguard in a small boat reacts to everyone's panic, the shark tips over the boat then appears underneath him to tear his leg off. We watch as it sinks slowly to the bottom. You can plainly see that the lifeguard is barefoot in the boat. The severed leg has a tennis shoe on. (01:02:15)
Continuity mistake: Orca's ID number normally reads MS 15 LF on both her port and starboard side at the bow. However, after Quint shouts, "Hooper, you idiot. Ain't you watchin it?" Orca's ID number reads M 15 L at starboard side and 15 LF at port. (01:16:30)
Other mistake: On the death certificate for Chrissie, the shark's first victim, the date of death is July 1st. But later, on the reward paper posted by the boy's mother, it says that the date of Alex's death was June 29th. Alex died after Chrissie, not before. Also, the form refers to the coroner as the "corner," and Jun 29th 1974 was a Saturday, not Sunday. (00:09:05 - 00:18:10)
Continuity mistake: When Brody is throwing chum in water and Quint is in the chair they show him wearing no socks and old tennis shoes. After Brody falls and then sets a new chum marker Quint has brown socks on and loafer type shoes. (01:12:45 - 01:14:00)
Continuity mistake: The number of barrels on the deck of the Orca changes from shot to shot, during the final scenes at sea. (01:41:00)
Continuity mistake: Throughout the film, Hooper wears on his left ring finger a gold bypass ring with a distinctive design and a small black stone, presumably black onyx. When Hooper is lowered in the shark cage, underwater the ring design differs; it's a classic style with a larger oval shape stone. (01:53:05)
Continuity mistake: Quint slams the machete into the wood beside the side cleat, and rigging lines. However, when the shark joins them aboard the boat and Quint is sliding towards its mouth, the machete's position changes - it is farther down towards the stern, note the black anti-slip mats. (01:44:30 - 01:57:00)
Continuity mistake: When Quint goes below deck to get the machete, with the intent to cut the barrel lines, the machete he takes is shiny and clean, with no rust or pit marks at all. Yet, when Quint holds it over his head and then embeds it into the side of the boat, the entire blade is rusty and full of pit marks. (01:44:40)
Continuity mistake: When Brody waits to board the ferry he says, "Charlie, take me over to those kids, will ya," and there's a painted board with 'Amity' attached to the ferry base. However, when they reach the other ferry landing the board with 'Amity' is gone, in sloshing water (even more visible in a deleted scene). It's the same side of the ferry, note the ferry Captain stationed at the permanent helm at only one side. The short haul Chappy Ferry's On Time scow was the stand-in for the fictitious Amity ferry. (00:11:40)
Revealing mistake: During Chrissie's attack, she clings to the buoy and cries, "Oh my God! Oh God!" In the next shot, as she is pulled away from the buoy, a wire (at about the height of the bell) that shimmers in the moonlight and bounces up and down with the buoy, runs from the buoy towards the right of the screen. It is not visible in any other shot. (00:04:35)
Visible crew/equipment: After Brody buys the sign supplies, when Hendricks shows up Brody places the box in the front seat, and as Hendricks tells Brody about the Boy Scouts, pay attention to the left window across the street, where we can see one of the local residents holding a camera and looking out the window facing the location shoot, taking pictures of the actors and film crew. The filming took place at the corner of Main St and S. Water St, Edgartown. (00:10:50)
Continuity mistake: In the close-up of the stern cleat as the shark pulls on the line, there are two large metal 'L' shape brackets screwed onto the corner of the wood of transom. Amazingly, these large brackets are not screwed into the wood in the close-up, as Brody winds the line round the cleat just a moment earlier. The metal brackets repeatedly appear and disappear. (01:42:30)
Continuity mistake: When Hooper is lowered into the water in the shark cage, in the following shots the ring he is wearing on his left hand vanishes and reappears in a few shots, such as when he drops the poison shark dart. (01:53:50)
