When Hobie first approaches the volleyball game, his backpack switches hands between shots. Then he lays it on the towel with the front side down. When the pickpocket approaches it, it is at an angle in one shot and flat again the next.
When Caroline turns off the shower for Arthur, the spray starts to taper off. In the next shot it has already completely stopped.
When the man with the metal detector first gets buzzed, two bikini-clad women - one in yellow and one in pink and blue - are near an umbrella behind him. When he starts to dig they walk off, but when he starts yelling they are by the umbrella again. Then, when the boy starts to play with his toy, these same two woman walk by in the background twice going in the same direction.
When Mitch and Dudley say good-bye, a woman in a spotted yellow bikini walks away from both of them, even though they face each other.
When Arthur gives Caroline the seal figurine, the head faces her left. In the next shot, it faces her right.
At approx. the 12:30 mark, when Duddly is demanding Mitch close the beach, the crew, camera, and lighting equipment are all clearly visible in Duddly's sunglasses reflection.