Factual error: A ham radio requires the person to hold down the button while talking. Numerous times in the movie they are talking without pushing the button.
Suggested correction: This is actually subtly addressed in the film. The magic which allows the radio to work across time also allows the two men to speak without pressing the button. There is a moment where Frank wonders what is going on with the radio and presses the button a few times to talk but then notices that he doesn't have to press the button to be heard.
If that was true, then it wouldn't make sense for them to continue to show Frank and John hitting the squawk bar throughout the film.
That is a separate issue. The mistake entry states that you need to hold the button to talk on a ham radio, which is true, but the magic ham radio in the film doesn't require it. If the actors continue to occasionally press the button that could be considered a character mistake but it could also simply be a force of habit by the characters.
Factual error: When Shep and his partner are looking for Frank on the docks in 1969, the camera pans to the left and we see a flash of the (completed) World Trade Center buildings just before the cameraman catches his error. In 1969 construction had only just begun on the towers.
Factual error: The radio used in the film is a Heathkit SB-301 receiver only, and is, in reality, incapable of transmitting.
Factual error: In the year 1969 Dennis Quaid reaches into a pile of Albums (vinyl) to play the "King". One of the albums in that pile is "Elvis In Concert" which was not released until 1977. (00:07:40)
Factual error: When the first change in the past takes place, the victims go from three to ten. One of the victims is John's mother. He would never be allowed to be part of an investigation with his mother as a victim.
Continuity mistake: After the first time the mother disappears from the family photo, and the father and son are talking after the father "saves" the first nurse, there is a wide shot of the board with the family picture on it - and it shows the mother in the picture. When the camera zooms in on the picture, the mother is gone again.
Continuity mistake: In the scene near the beginning where John is looking through a scrap book, he turns the page and there are articles on the page, but when the camera does a close-up on the scrapbook, there is a whole newspaper with the scrapbook.
Continuity mistake: When John is telling Frank Sr. about game 2 and about Al Weiss, the scene changes to the fireman sitting near a TV watching the game. As the camera pans around a fireman with a moustache is sitting behind the old guy in the chair, but in the following shot he is sitting at his side. (00:31:40)
Continuity mistake: When Satch is talking with Frank after discovering his wallet underneath a dead girl, he lifts up Frank's driving licence. Four of Satch's fingers are on the front side of the licence, but when the shot changes, Satch holds the licence with three fingers on the front and a finger and thumb at the back. (01:24:00)
Continuity mistake: At the very end when the family and friends are playing baseball in the park, the first ball Frank hits smashes into the headlight on Gordo's Benz. The front-end license plate is shown for a few seconds, and even though it is blurry, it appears to be several numbers and maybe a letter or two. But when the next shot of it is clear, it says "1YAHOO".
Continuity mistake: When it cuts to 10th October 1999, John's girlfriend leaves and he walks to his living room and gets a drink. When he puts his gun on the table it slides, leaving the gun at an angle on the table, yet in the next shot the gun is straight. (00:12:10)
Continuity mistake: In the scene where Dennis Quaid is in the Buxton building and he finds the girl, in the first shot when it cuts to her, she is lying on her side, but in the following shot she is flat on her back. (00:37:00)
Continuity mistake: At the beginning of the film when Frank is pushing John and he runs off into the house, after Frank's little conversation with his wife, he takes out a cigarette and is looking down towards the floor. In the following shot he is looking straight ahead. (00:09:30)
Continuity mistake: When Frank is on the scene of the overturned fuel tanker, a man wearing a beige coat and grey hat says, "Only the manhole leads to the vault", and a fireman stands on Frank's right, yet in the next shot he is on the far left of the screen. (00:02:30)
Continuity mistake: When Frank has survived the Buxton fire and is trying to reach his son in the future over the radio, his son from that time walks in and sits on Frank's knee. He takes a chewing gum out of the silver wrapper in his right hand, but in the following shot it is now in his left. (00:42:25)
Continuity mistake: In the middle of the film, Jim Caviezel is interrogating the "suspected killer", the scene opens looking at the clock, it says "1.30pm", then a few seconds later in the it cuts to the black cop, there is a clock on the wall behind him that says "12.15pm". (01:10:30)
Continuity mistake: In the opening scene, Dennis Quaid goes to rescue a guy in a room, he opens the hatch where the guy is and in one shot he steps into the room. In the following shot he is stepping into the room again. (00:03:50)
Continuity mistake: When the killer hits Dennis Quaid and he falls on the floor, the killer then takes his wallet and throws it in the cubicle next to the toilet, yet when he moves Dennis Quaid into the cubicle the wallet has disappeared and reappeared in the next cubicle along. (01:12:50)