Continuity mistake: When Klaus and Claudia greet the Chipmunks and Chipettes at the airport after the girls' balloon lands on the ground, Alvin threatens them with a harpoon having two red feathers attached near the tip. But in the next shot no feathers are hanging from the harpoon, and the balloon temporarily changes to the chipmunks' balloon. Suddenly Simon notices a garbage hatch on the plane and grabs the harpoon from Alvin, but now there are two green feathers on it instead. (01:05:55)
Continuity mistake: When the Chipmunks and Chipettes are nearing the airport, they turn around and notice a plane approaching. Stuck to their balloon's basket are several harpoons, but as the plane's wing sends the balloon careening towards the ground, all of the harpoons have vanished. (01:05:35)
Continuity mistake: About 10 minutes into the movie, the chipmunks and chippettes first meet Claus and Claudia. Claudia is wearing a pink outfit, so to match, she is wearing pink lipstick and nail polish (when she and Claus are sitting together). But when they do meet the chipmunks, her lipstick and nail polish turn red and stay red for the remainder of the scene.
Continuity mistake: As Claudia pedals on her stationary bicycle, a call comes in from Mexico. So she picks up the phone and you can see how a cord is attached near the microphone. When the shot changes to Klaus tanning in his booth, Claudia is visible through its window - but now she's talking on a cordless phone instead. (00:23:55)
Continuity mistake: When Alvin and Brittany are in Athens, they start arguing over who's the hottest act in rock and roll. Notice how he's standing next to a green stool in front of some wooden containers loaded with grapes and apples. But after Alvin says "No you don't!", Brittany loses her cool and walks over to challenge him. However he's suddenly off-screen somewhere and nowhere near the fruit stand. (00:34:10)
Continuity mistake: When you first see the arcade that the kids are playing you can see the Chippettes are winning on the map and they are going through Asia, but when you see it again a few shots later, they are flying around Europe.