Continuity mistake: After Dory reads the wall map while she's in the glass carafe, when Hank hides behind the rolling cabinet there's a long shot of the corridor with him at the far wall, then in the next shot from behind Hank a drinking fountain has suddenly appeared on the wall to the left between two pictures.
Continuity mistake: When Carol, the MLI employee, is first seen carrying the white bucket in the corridor and also when Carol thinks she located Hank, the bucket has absolutely no writing on it where the handle's attached on both sides, but when Dory looks down at the bucket suddenly "Destiny" is written on it.
Continuity mistake: When Dory and Hank are in the stroller trying to get to the Open Ocean exhibit, Hank steers the stroller right into a girl wearing a striped top and holding a cup of popcorn, but a few shots later that same girl is now wearing a light pink top when she's on her knees with the spilled popcorn.
Continuity mistake: While Hank camouflages himself as part of the yellow banister, Carol, the MLI employee, walks down the stairs with the bucket, and when she sets it down the handle falls to the side of the bucket facing away from Dory toward the staircase, but in the next shot the handle is facing the opposite way. Additionally, the bucket's distance from the floor's black-yellow caution stripes decreases between these two shots.
Factual error: When the bucket launches, Marlin and Nemo fly into a small plastic tank with a toy fish. The tank was filled with freshwater, which means Marlin and Nemo would have died in there before they had a chance to get out.
Continuity mistake: At the end, the truck jumps off the cliff into the sea. We see the truck flip over 90° so the trailer doors are starting to face forwards and the cab faces back, upside down. Camera changes and the truck has gone back to being right way up, and not rotated nearly as much.