When Sten is carried out of the water draped around his friend's back, there is no sign of a shark bite to his right side, but when he reaches the community, the shark bite to his right side is visible.
Keaty explains the rules of cricket and asks if anyone still doesn't understand. Richard and Étienne both raise their left hands. The camera angle changes; when Richard is shown again, he is raising his right arm instead.
During their stroll on the beach, Francoise and Richard walk along the water with Francoise on the shore side; yet in a close-up of her, the water is behind her. And again in the next shot Francoise and Richard are both standing knee-deep in the water, although they haven't been moving for quite a while.
When Richard, Etienne and Francoise are swimming towards the island and Etienne and Francoise pull a prank on Richard. You can see when Francoise plays the "shark" approaching Richard, when his wet padded hair stands up once then he pulls his hair back, but as his hair gets wet again it shows his hair up without him pulling his hair back, then his hair wet and down after his hair appeared to be standing.
The picture used for the virtual postcard near the end of the movie is not the same picture taken back at the beach, because some of the minor and main characters have changed positions and/or struck a different pose.