Factual error: When the General is shot as he comes out of his car, you can see an electronic black parking meter behind him. The film is set in 1996 and this kind of parking meter wasn't introduced until 1999.
Factual error: When the two Gardai (Police officers) are watching over Guerin's house after she was shot in the leg they are sitting in their car drinking coffee from Starbucks disposable cups. Starbucks did not enter the Irish market until long after the events dipected in this film. In Ireland at that time it would be more likely that they would be drinking tea out of a flask.
Factual error: In one of the scenes in the pub, there is a new model of the Heineken draught tap seen behind the bar. Those taps did not come in until 2000 and the film is set in 1996.
Continuity mistake: In the scene where Veronica is sitting at her computer working and her husband is upset with her, she disconnects her headphones from the stereo, pulls them off, and puts them around her neck. When she stands up and starts dancing to the music, they're on her head and she pulls them off again.
Continuity mistake: When Veronica and her work colleagues are in the pub, there is a football match on the television. In the background you can seen the match and Eric Cantona just standing on the pitch. All the fans in the pub celebrate but nothing had happened in the game. Cantona was still just standing there.
Factual error: When Veronica is driving back from the court house just before she is murdered, you can see a car in the background (a Mercedes M-class). The license plate begins with "02", meaning it was bought in 2002, but the film is set in 1996 and the M-class wasn't even available until 1998.
Factual error: At the very start of Veronica Guerin you see Dublin port and an Irish Ferries ship called the Ulysses. Veronica Guerin is set in 1994-1996 but the Ulysses was built around 1999.
Factual error: When Veronica is in hospital she seems to be flicking around different TV channels and keeps finding Irish news programs. At the time these events took place, only one Irish station, RTE1, was broadcasting news in English. All the clips shown on the TV are from RTE1's news - they just show different newsreaders from the same station.