Continuity mistake: Allie has just walked into Noah's barn and is admiring his carpentry. The way her blue scarf is tied around her head changes from shot to shot. (01:16:50)
Audio problem: When Noah and Martha exit the "dream house", Allie's head does not move (she looks down all the time), nor do her lips move while she pronounces parting words to Martha.
Revealing mistake: When Noah and Allie meet outside the movie theatre and later dance in the intersection of the streets, the viewer can see their breath. It is very cold outside and Noah is wearing a heavy jacket. Summer in South Carolina is oppressively hot, even at night. (00:17:00)
Other mistake: In one of the beginning scenes, when Noah and Fin are at the fair, you see Allie and Sarah on the bumper cars. Allie bumps into Sarah, and you can see and hear Sarah yell "Rachel," which is actually the name of the actress who plays Allie - Rachel McAdams. (00:05:20)
Factual error: The mansion Allie is staying in over the summer is Boone Hall Plantation in South Carolina, near Charleston. It was built in the 1930's, so factually the house couldn't have been in the family as long as the characters make it seem. A lot of the filming was also done in Kiawah, an island near Folly Beach.
Continuity mistake: When Allie has returned to Noah and they are on the boat in the area with all of the swans, her hair is in a bun. Before it starts raining in the next scene, her hair is only half up and curled as if it had been down all along.
Visible crew/equipment: When Allie gets back into her car, after her first visit to Noah's house, you can see a microphone - crew member on the back of the exterior mirror. (01:12:00)
Continuity mistake: When Allie and Noah go to the beach and are playing in the surf, her ponytail is wet when viewed from the beach and dry when viewed from the ocean. (00:22:00)
Continuity mistake: When Allie crashes her car into the fence, Noah has a beer in his hand. As Allie swings the car around, you can see Noah in the background and the beer has disappeared.
Continuity mistake: When Noah and Allie are preparing to make love for the first time, they slowly undress and lower down onto the floor. The front shot of Allie shows that her hair is tied back in a Pollyanna hairstyle, but when she kneels down, the back shot shows that her hair is completely out.
Continuity mistake: During Noah and Allie's first date, when Noah decides to lie down in the street, his head is lined up with the double yellow center line on the road. When Allie decides to try it, Noah has moved to nearly the middle of the right lane. (00:15:00)
Continuity mistake: When Allie drives off after she gets her letters and she and Noah argue, Noah walks significantly past the back of the car and puts his hands on his head. When Allie gets in, he's standing up by the front bumper still with his hands on his head.
Factual error: When Allie is looking at the moon before entering the house with Noah, there are a few contrails barely visible in the sky, but there couldn't have been any contrails back in those days because planes didn't fly that high or give off the same exhaust as modern-day planes. (00:29:10)
Audio problem: When Noah and Allie are at the dilapidated old house, when Allie says 'This place is gigantic' her words don't match her mouth moving. (00:30:00)
Continuity mistake: When Noah hears that Ally has gone he goes to her house and there is a cement driveway but in all other scenes at the house the driveway is gravel.
Continuity mistake: When Allie and Noah are making love after the seven years when they fall at the feather pillow, notice at the back there is a white book shelf which is at the right and only can be seen half of it. A few seconds later in the same camera position the book shelf is at the centre.
Continuity mistake: When Allie tries her wedding dress on and the ladies are all squealing around her, she goes back and forth between having her earrings on and having no earrings on.
Factual error: Allie and Noah pass a small grocery store sign in window (Peaches 2 1/2 size 3/$1). That price is correct for about 1962, but not the time frame of early 1940s.
Continuity mistake: Older Noah goes to see the doctor who listens to his heart. On the wall are two x-ray films. The x-rays flip between shots, as evident by the position of the heart. At first it is on the left. When Noah gets up the heart is now on the right. (01:08:45)
Continuity mistake: At the very end, on the morning after Noah and Allie had died, the way the two hold each other's hands are different between shots. Note Noah's pinkie.
