When following the Ahab, Xander and Yelena drive on left side of the river, thus they should turn right to go over the bridge. They go left.
When Xander arrives in Colombia, his jacket disappears and reappears between shots.
The tattoos on Xander's arm switch throughout the movie.
When Xander throws the bombs that start the avalanche he opens his jacket to take out the explosives. In the next shot his jacket is closed but there is too little time to zip it up.
The logo on the front of the Pontiac GTO disappears and reappears between shots throughout the movie.
The NSA wouldn't send agents overseas - that is what the CIA is supposed to do. The NSA's work is limited to the collection and analysis of foreign communications and foreign signals intelligence; it does not perform field or human intelligence activities.
When Yelena wants a wire transfer from Xander, all she gives him is an account number. However, to do a wire transfer, you need the banking code in addition to the account number. She neither mentions this not gives it to him.
The National Security Agency is solely responsible for communications intelligence. They are tasked with securing U.S. communications and trying to intercept and decode other countries' communications. They do not have field operators of the type portrayed in the movie. If they had actionable intelligence it would be turned over to the CIA for their use. Also, the NSA is forbidden to intercept communication originating in the U.S. Exceptions require approval from DOJ and court review process and are very rare.
An average-sized dry avalanche travels around 80 mph and it's nearly impossible for someone to outrun an avalanche or even have time to get out of the way.
Avalanches can move much faster than a skier can typically ski, especially large or wet avalanches.
When XXX arrives in Prague, one of the first exterior shots is a street lined with Romanian flags.
On the street, called Nerudova, are both the Italian and the Romanian embassies. So, one of the flags is the Italian flag.
When Yelena pulls onto the bridge towards the end of the movie, the GTO is maroon rather than blue, then changes back in later shots. This appears to be a continuity error, but the GTO is painted with color-shifting paint which 'shifts' depending on the angle of the light source and the viewing angle. This shift can also be seen earlier in the film as Cage is captured after the escaping from the cafe.
When Xander Cage steals the red Chevrolet Corvette from the California Senator at the country club, he jams the gear shift into first gear and then continues to drive in reverse.
When XXX sneaks into Yorgi's lair to rescue Yelena, he jumps down and pushes his hand against a 'brick' wall - the wall gives noticeably indicating it is not solid.
In the slow motion shot of the Corvette going off the side of the bridge, the car bursts into flames a split second before hitting the ground.
When Xander is using the heat seeker rocket, he adjusts the screen on the side so he can see it. In the shot where we can see the screen, there is nothing on it.
Xander parachutes from a car that he drove over the side of a bridge. The camera man inexplicably pans to the side even though Xander's trajectory is is straight down.
When X picks up the rocket launcher, you can clearly see that it is a camcorder with a flip out screen, with some extra add on's. (Pipes and a box.) The Date, Time, and Reset buttons are clearly visible.
Crew member in orange jacket is reflected in the window of the restaurant where XXX takes Yelena for lunch.
When Xander and Yelena are seen in the restaurant from the sniper's perspective, a crew member is reflected in the window (wearing a baseball cap and red jacket).
When Xander is Sky-surfing towards the communications centre in one of the angles you can see the shadow of a helicopter on the ground below him.
As Xander cuts the parachute free after landing on Ahab, a cameraman is clearly visible on the front of the boat.
There is no way that the scene racing up the river in Prague could have taken place as it did, as there is a weir in the way which he would not have been able to cross.
Ahab is supposed to cruise the world's oceans after passing through Prague; there are dams and weirs (at least one right in the middle of Prague) which would prevent it.
Ahab was meant to travel to different continents, but the river through Prague flows south to north, and as Ahab was cruising south, it was heading inland.
When Xander is captured by the Americans (after skateboarding down the railings on a dessert tray) he is taken into a concert hall. The exterior shot is of the Rudolfinum Concert Hall in Prague, however the interior shot is of a completely different building, the Prague National Theater (notable for it's red velvet seating). In addition, on the director commentary, the director explains how that theater (the National Theater) is where Wolfgang Amadeus Mozart premiered "Don Giovanni." This is also incorrect as that opera premiered at the Estates Theater, another theater in Prague but not pictured in xXx.
xXx is having a lunch with Yelena at the Opera restaurant. Then the mess with the sniper begins and he escapes but is captured. The place of his capture is at the foot of the hill, on which Prague Castle stands and this is on the other side of the river Vltava.
Shavers claims to have graduated magna cum laude from MIT. MIT does not award Latin honors with degrees.
The double swing doors in the agency showing a map of the world does not have New Zealand on it, which is quite a big land mass to miss.
When Xander parachutes into the compound, it appears he pulls his silver handle on the left ribcage, on his parachute to jettison the canopy. In reality, the silver handle is the reserve parachute deployment handle. In real life he would have pulled the cutaway handle on his right ribcage, which is the cutaway handle. Pulling the reserve handle without pulling the cutaway handle will result in a 2-canopy out situation, which would be potentially dangerous.
The Russian engineers actually speak Russian with a Czech accent and later when the rocket is about to explode you can hear them panicking in Czech.