Continuity mistake: In the final shot, just as the credits are rolling, the British warships are sailing away with the sun setting behind them. In an earlier scene the radio commentator says that the sun is setting and a shot of the sun touching the surface of the sea is shown.
Continuity mistake: At the end of the film the fleet were instructed to sail towards the burning vessel, which would have meant that they were travelling west - into the setting sun. Given the location of Montevideo on the River Plate it is somewhat dubious that the sun would set over the sea even at that time of year.
Factual error: When the filmmakers were choosing existing warships to play the roles of the ships in the battle, they didn't quite match up some of the details. The Graf Spee is represented by USS Salem which has three triple gun turrets - yet in the Captain's cabin is a photograph of the real Graf Spee which had just two turrets. Likewise, HMS Ajax is represented by a Sheffield class cruiser with four triple gun turrets - yet in the fire control area there are just eight lights to indicate guns ready to fire.
Factual error: Some of the gun crews (usually skulking behind the guns) on the "Graf Spee" are wearing their American helmets. (U.S. Navy refused permission for German helmets to be worn, but regardless of the reason it is still a movie mistake.)
Revealing mistake: When the German cruiser Graf Spee is seen leaving Montevideo harbour for the last time it is flying the American Stars and Stripes flag from the aft observation platform tower.
Continuity mistake: In the scene as morning breaks before Graff Spee is sighted, Cdre Harewood is wearing the lace of a Rear Admiral, he is not promoted to Rear Admiral until after the battle after.
Continuity mistake: When the gun firing has ceased, the German boarding officer tells the British prisoners they will be freed in the morning. As they are whooping and cheering, Captain Dove of the Africa Shell goes out to view the harbour and in the melee loses his cap. When he looks at the scene his cap has reappeared on his head.