Continuity mistake: When Brody thinks he spots a shark, he rings his bell, then begins to descend the watch tower. In one shot you can see a woman with blonde hair, sitting on a beach-chair, at the bottom of the watch-tower. In the next overhead shot, as Brody runs across the beach, the same woman now suddenly has an orange hat on. (00:44:50)
Continuity mistake: When the shark is attacking the catamarans with the teenagers aboard, in one shot you see Andy fall backwards, still on the catamaran, and he is barefoot. He is then knocked in the water, and when his friends pull him back out of the water on, he now has white trainers on. (01:20:10 - 01:21:15)
Continuity mistake: In the scene when Chief Brody, his wife & deputy come across the sail boat named "Tina's Joy", they find Tina in it, and during this scene Chief Brody's jacket is placed on Tina's shoulders. The Chief then leaves the sailboat in search of the other teens. Later scenes show the Chief wearing this jacket when in fact he left it with Tina.
Continuity mistake: At the end of the movie when the Chief has killed the shark, you see his son Shawn cheering, with his hair completely wet and messed. By the time the Chief paddles over, Shawn's hair is now perfect; dry, and combed neatly...
Continuity mistake: When Tina is running away from Eddie in the building on the beach, you see that the building is casting a huge shadow across the beach. But when it cuts to the next shot in which they are running past all their friends, there is no shadow being cast on the shore from the building. (00:26:35)
Continuity mistake: In the scene where Brody drives his jeep onto the ferry he drives it to the edge. Yet in the next shot when it reaches the other side the jeep is about two feet from the edge.
Continuity mistake: When Chief Brody comes home drunk, he finds Ellen and Hendricks sitting talking and he then comes in and pours himself and Hendricks a drink, in order to celebrate the fact that Brody has just given Hendricks his Chief of Police badge. Back and forth between shots, the amount of drink in Brody's glass differs. (00:56:05)