Revealing mistake: When Vicky and Cristina arrive at Barcelona they walk towards the camera, and the people behind who are real passengers waiting for a taxi stare at the actresses and film crew and even take pictures of them.
Character mistake: After sleeping with Juan Antonio, Vicky returns to the library to study and do research. The narrator says that she cannot stop thinking about Javier, the actor's real first name, not the name of the character Juan Antonio.
Visible crew/equipment: When Vicky and Cristina are eating with Judy and her husband, a man standing in front of Vicky is reflected on her sunglasses. Wide angles, however, they're seated around a table, with no one else around.
Continuity mistake: When Vicky is wounded in her left hand, the wound disappears completely before that scene is over.
Factual error: We're told over and over that Vicky is an expert on Barcelona and Catalonia, for she has written a thesis. She visits Avilés (Asturias) with Juan Antonio, where he tells her he was born a few blocks from there; however, during their dinner at night the actress mistakes and tells him that he's from Catalonia, instead of Asturian. Anyone with a such an expertise on Catalonia will know that. Besides, it's not real life, but a screenplay, so either Woody Allen screwed up, or the actress did.
Visible crew/equipment: When Vicky is trying on many dresses for her last date with Juan Antonio, a crew member's legs are reflected on the mirror on the wall. (01:22:54)
Continuity mistake: While Vicky and Cristina are having their first lunch with Judy and her husband, the position of Judy's hand on the glass of wine keeps changing randomly without any continuity depending on the shot.
Visible crew/equipment: In the restaurant were Juan Antonio invites the girls to Oviedo, lighting equipment and screens are reflected on Vicky's glass of wine.
