Goofs

When Tess (in Anna's body) wakes up after the swap, she makes her way out of Anna's room and the door, which was removed the night before, is still there. In subsequent shots, and conversations, it's obvious that the door isn't supposed to be there.

When Tess is in Anna's body she finds out that Anna has pierced her navel, but a short while earlier, Tess tells Anna to pull down her shirt and her navel isn't pierced.

When Anna gets home from school and finds her brother in her room her hair is all ruffed up. When she goes into the garage to practice her hair is smooth and sleek, then when they are finished her hair is all ruffed up again.

Tess has Anna's door removed, next morning Anna and Tess "Switch" and stop half-way down the stairs. Behind them Anna's door with her sign "Parental Advisory Stay Out Of My Room!" is still there.

When Anna returns home from school on the Thursday, she finds Harry banging on her guitar with drumsticks in her room upstairs. She chases Harry downstairs and goes straight into the garage and picks her guitar which suddenly appeared downstairs.

When Anna submits her paper about George Orwell's "1984", she writes that this is an American novel. It is a British novel.

Anna states in the movie that she plays her dad's old Telecaster. The guitar used in the film is a Fender Telesonic. This model wasn't released until 1998, meaning it can't be considered 'old' during the events of the film.

When asked, Anna tells Jake that she plays her "dad's old Telecaster". The guitar she plays in the movie is not a Telecaster but a Telesonic that wasn't produced and sold until July of 1998. However, the Telesonic is a guitar made by Fender themselves and based heavily on the design of the Telecaster. It is considered a 'supersonic' version of the original guitar, hence the name 'Telesonic'. It would be quite reasonable, for the sake of keeping explanation to a minimum, for Anna to refer to her guitar as a Telecaster.

When Tess (in Anna's body) is trying to talk with Stacey before class, the teacher Mrs. Brown says "alright everybody - let's take our seats for the test". Stacey then tells Anna "sit with me?" however students wouldn't be allowed to pick and choose their own seating arrangements, especially when a test was being given.

However, Stacey could have been using the phrase in a friendly manner to allow her to let her guard down as they sit in their regular seats. This could also be a test outside of normal classes where students from different classes are brought into the same room, meaning there would be no assigned seating in advance.

When Anna (in Tess's body) and Tess (in Anna's body) are in the car. You can clearly see the outside of the window is fake. You see that the same sign keeps appearing over and over again (on "Anna's" side)

The school scenes were shot at Palisades Charter High School in California. The crew renamed the school to "Sunset Ridge High School", but in the gym scenes, the Pali logo (a "P") is clearly seen in the middle of the court.

When Ryan is driving to school and reaches for Tess's hands, you can tell that his Navigator is in Park although he is supposed to be driving.

When Tess (in Anna's body) is walking she is carrying two bags. Her Palm beeps and she drops her bags which are empty.

When Tess is trying to get the underwear off that is tied around Harry's head, she snips little pieces of fabric, whereas if she cut the elastic band, it would come off immediately.

At the rehearsal dinner, when Tess and Anna switch back, you can hear Grandpa shout "Earthquake!" but in the camera shot you see him looking around and his lips are not moving.

When Anna plays guitar, some of the chords she makes are different than what's being heard.

When Tess (in Anna's body) is asking Jake for a ride home he tells her no because she wasn't the girl he thought she was. He then mentions what she did to Stacey Hinkhouse's test. Tess says that she didn't even know what she was doing and she didn't mean to do that, but her lips aren't moving.

In all but the third close shot of the drummer at the House of Blues auditions (while he mouths at Anna), the drums you hear are different from those he plays (you hear cymbals when he never actually strikes any, etc.). In the third shot, the audio and video appear to be synchronized.

During the House of Blues audition, in the intro, you see the backup guitarist with the black stratocaster playing. Since Tess (in Anna's body) isn't playing, palm mutes are heard. It looks as if the backup guitarist is playing the palm mutes, but her palm is nowhere near the bridge or on the strings. She's strumming the guitar, and Anna originally plays the palm mutes.

When Anna (Tess) needs a ride home and asks Jake if he take her, the camera is reflected in Jake's helmet.

When Tess (in Anna's body) enters her room with Harry, the shadow of the camera falls on the door.

When Tess is dropped off after Ryan drives the kids to school, she gets her hair cut and highlighted, her ear pierced, does a considerable amount of shopping, and has a number of patient appointments and still manages to pick up Anna at lunch time. That's a lot of activity in one morning.

When Tess (in Anna's body) asks Jake for a ride home, the boom mic is reflected in Jake's glass shield of his helmet.

When Anna (in Tess's body) was woken up by Tess (in Anna's body), Anna tried to fix her hair as she got up but Anna was fixing her hair like she was still Tess - brushing the ends of her short hair. As "Anna", she should have instead tried touching her "long" hair.

Anna knows who Keith Richards is just from her mother mentioning The Rolling Stones. However, earlier in the movie, she doesn't know who Stevie Nicks is despite being the frontwoman of a rock band herself.