When William arrives at Chomp City, he puts his shell phone away. But after he bumps into the red hammerhead shark, his phone reappears in his left fin.
Baby Shark doesn't take his bracelet off when he gets on the top bunk bed. But when he buries himself under the plush toys, his bracelet disappears.
At William's birthday party, the birthday cake has four candles. But when it's sliced into five pieces, each piece has a candle, showing that there are five candles.
During the song, "Oceans Apart", when Baby Shark is looking through the pizza restaurant window, his star mark, which is on his left cheek, is on his right cheek through his reflection.