Factual error: In the shot of the infield at the Saratoga racetrack several Canada geese are shown landing. However, the calls inserted on the soundtrack are the quacks of mallard ducks not the honks of Canada geese.
Factual error: Many of the main characters are using modern-day binoculars (black, plastic) throughout the entire movie.
Factual error: In the shot where Pimlico racetrack is shown and the dateline shows November 1, 1938, the Maryland flag is upside down. The black and gold squares should be at the inside top and they are not. (01:35:10)
Continuity mistake: In the race for the $100,000 purse (that Rosemont wins), just after Seabiscuit takes the lead, there's a closeup of Seabiscuit's head and Pollard's right leg - Pollard is wearing the brace he made later in the movie after his leg was shattered. Obviously, the shot was taken from those filmed for the Santa Anita race later in the film. (01:17:40)
Factual error: In the scene where Seabiscuit is weaned from his mother, the narrator says that he was six months old at the time. However, the foal used in the movie is less than one month old. (00:43:30)
Factual error: Jockeys did not wear goggles and their skullcaps did not have chinstraps in the 1930's. Protective equipment for jockeys was practically non-existent during Seabiscuit's racing days. (00:28:10)
Factual error: Two men are trying to start a John Deere Model D tractor, which backfires, startling the horse. The wrong sound effect is used; it sounds like a V8 engine being turned over by an electric starter. The tractor's flywheel, on the left side, is shown stationary. Turning the flywheel by hand is the usual starting procedure for a JD tractor of '30s vintage. For over 40 years John Deere tractors used a two-cylinder engine, which make a distinctive popping exhaust sound. The movie is right on one thing, JD tractors could backfire.
Factual error: Pollard did not lose his sight in a fight, as the film suggests. He lost it when he was galloping a horse for exercise and a horse going in the opposite direction kicked up a clod of dirt that struck him at the base of skull and knocked out the cerebellum on his left lobe. (right side, left lobe).
Factual error: Statements are made in the movie that War Admiral was "almost 18 hands" tall, when in reality, War Admiral was only 15.3 hands tall. War Admiral's nickname was "the giant killer." Seabiscuit stood 15.2 hands tall. Both horses were considered very small as racehorses.
Revealing mistake: In the beginning scene, where the horse tamer is chasing the "mustangs", you can occasionally see the glint of a horseshoe on various "wild horses". (00:03:40)
Factual error: The flat top inside rail at Santa Anita racetrack is a new style safety rail. (00:59:50)
Revealing mistake: In one scene we get a view of people standing beside a vintage automobile. A license plate is mounted on the vehicle's rear fender and we get a clear view of the back of the license plate. The plate appears to be made out of aluminum and pressed into the plate is a relief image of an antique automobile. What we are seeing is a modern license plate issued by some state for a vintage automobiles. (In Iowa a car must be at least 25 years old to qualify for such a special plate.)
Other mistake: When Marcela and Howard are viewing Seabiscuit for the first time (when he's weaving all over the place) it looks like it was done before as Seabiscuit follows a thin ribbon of disturbed ground that is weaving in and out. Its unlikely any other horse would be weaving like that.
Continuity mistake: When Seabiscuit races War Admiral he has a white snip on his nose and no white markings on his feet, but in the final race of the movie there is no white snip on his nose and that horse has white socks (coloring) on his front feet. (01:43:45 - 02:09:55)
Factual error: When they are heading east to race with War Admiral, there is a scene at the Los Angeles Union Station. This is in 1938; the station was not opened until the following year. (01:20:00)
Factual error: Pollard never told Smith and Howard he was blind in one eye. He kept it a secret, presumably until the eye paled or his fame had dropped off and no one really cared any more if he was blind or not.