Factual error: The double decker bus in the Waterloo (York Road) scene has the number 43 on it. Paul Greengrass told the driver to put any number up on the front destination blind. The 43 does not go to Waterloo Station, but goes to London Bridge Station.
Continuity mistake: When Pamela Landy is looking at Jason Bourne's induction paperwork, the date of his induction is 06-01-1999. However, the date of his first assassination (Neski) is 1998. The assassination of Kyriacou is also listed as having taken place in 1998. Both dates are obviously before he had completed the Treadstone induction. (01:11:55 - 01:13:25)
Continuity mistake: When Desh is chasing Nikki and Bourne is chasing Desh, in a shot of Bourne from overhead, he is wearing black converse type tennis shoes (black with white rubber on the toes). As the chase continues, Bourne's shoes are shown several times to be solid black.
Continuity mistake: The conversation Bourne has with Landy at the end of The Bourne Supremacy is repeated in this film, about an hour and fifteen minutes in - the conversation is absolutely word-for-word identical, so clearly it's the same one. However, in Supremacy, it is a bright, sunny day, but in Ultimatum, the weather is overcast with snow on the ground. Landy's phone rings in Supremacy, but vibrates in Ultimatum. Finally, the other agent doesn't enter her office during the phone call in Supremacy.
Other mistake: At the beginning of the New York chase sequence where Bourne is walking down the street, you can see an Asian man smiling right into the camera for a second.
Factual error: When Bourne is traveling to London on the Eurostar from Paris, immediately after the 'flashback' where Marie floats away after being killed, there are two helicopter shots of the Eurostar traveling to London. The second (far away) shot shows the train passing over a motorway. The train is actually traveling towards Paris, and therefore away from London. The motorway is the M20 and the bridge is approximately 3 miles west of junction 9 for Ashford (Kent). The train would have been 10 minutes away from entering the Channel Tunnel. (00:13:45)
Factual error: When Jason is at the internet cafe googling the financial company, the address that comes up for Sydney is not technically possible. The street name (Market Street) is real, but the street number was 18017 which is not possible as the street is only a few blocks long and ends at about 400. (00:29:00)
Continuity mistake: When Nicky is first seen in the movie, with Bourne pointing a gun at her, her hair changes between shots.
Continuity mistake: At the end of the movie, in the flashback when Bourne recalls his training process several years ago, Hirsch looks younger, but Bourne looks just like the present date, with an edgy and thin face, opposite to the round-childish face that he had then (which we are reminded of during all the movie via photos in his portfolio).Sacha
Continuity mistake: When Desh goes to meet Nicki, he parks his scooter. Walking behind him(from left to right) is a guy wearing a black shirt with orange stripes. The camera then switches to Bourne and then back to Desh. The man in the shirt is now seen walking towards Desh(from the left) but is still at least 40 feet away from him. (00:53:40)
Other mistake: When Jason is in the Internet Cafe in London he Googles for Sewell and Marbury, when he gets the results he doesn't have "The "AND" operator is unnecessary - we include all search terms by default. [details]" which should have been displayed just below the search box. (00:28:55)