Continuity mistake: Near the start, Mirabel is given a basket with items such as bucket and spade, windmils etc. When given the basket the buckets are towards her. When the shot changes the buckets are away from her. (00:07:15)
Plot hole: Johnny's dad jumps in his truck and gets to Johnny in moments. That same journey was shown to be an overnight bus journey for everyone else.
Other mistake: When the car stops and Chase is left on the curb the door is closed and it magically goes through him. (00:11:54)
Continuity mistake: While at Dino Stop, Katie convinces her dad not to play it safe and to take a chance to save the world. Rick agrees and extends his left hand for the "all hands, Mitchell family on three." In the closeup we see Katie put in her right hand, but in the wide shot Katie's left hand pulls out. Also, note that in the closeup both Katie's and Aaron's positions between their parents are switched. (00:45:00)
Character mistake: When Tim and Ted enter the school, we can hear a group of girls including Tabitha singing: "The wheels on the bus go Pi-r-squared / circumference all around." But π r² equals the area of a circle, not the circumference (which is 2πr). (00:36:34)
Continuity mistake: When watching the water retreat after Sisu falls, a view from behind the characters shows Noi sitting on Tuk Tuk. The very next cut shows Tong picking her up from the ground. (01:18:01)
Factual error: Steve Trevor tells Aquaman that he is a Colonel in the US Army. But he is wearing First Lieutenant bars on his uniform.
Factual error: All Arabic texts in the film suffer from wrong directional rendering. Arabic is a right-to-left language. Its letters have different joined and disjoined forms. The film, however, has rendered Arabic texts from left to right in disjoined letters. These texts aren't semantically wrong, though. For example, deciphering the Arabic message at 0:40:45 point gives "أليس "التنين فنان؟ Translation: "Isn't the Dragon an artist?" The film has even adopted a good font for them.
Factual error: During the escape from the farmers market a red London bus is in the background. Those busses aren't used in Gloucester.
Plot hole: Alberto didn't sign up for the Portorosso Cup, and he enters anyway. This should've gotten Luca disqualified.
Continuity mistake: When Tom knocks down the bike at the car, the position of the fallen clothes changes between shots.
Continuity mistake: While Porky is rapping, Al - G and Dom swap spots between shots.