Continuity mistake: Following Chance's run-in with the porcupine: Right after Animal Control pulled the needles out of his face/snout, he was visibly wounded, with giant red makings which appear on the right side of his face. Then, while the 3 pets are looking down at their hometown which they just realised is only a little distance from where they are (Sassy had just pointed this out to the dogs), those red wounds are now on the left side of Chance's face. Then, by the end of movie the same markings mysteriously disappear and are completely gone in the final scene.
Revealing mistake: Near the start of the journey, there is a shot of Chance and Shadow running through a creek. This is followed by a shot of Shadow coming toward the camera. As she turns off to the left screen, something on the bottom moves with her. It is likely a guide for the cat to follow.
Visible crew/equipment: When Kate finishes writing the note, she places it on the table, grabs her hat and leaves the barn (or shack). The door slams shut and the blast of air knocks the note off the table and onto the floor. Just for a brief second after the note has fallen, something that resembles a foot can be seen in the upper left-hand corner.
Continuity mistake: During the first night when the pets hear animal noises and are scared, there are at least two angles when you can see it was shot during the day. It is dark in the other shots.
Visible crew/equipment: When Chance is mingling at the wedding, the camera shows his point of view going under a table. The shadow of the camera (with wires) can be seen on the left side of the screen.
Audio problem: When Sassy shakes her head during mealtime in the kitchen of the woman temporarily watching the animals, a bell rings although no cat bell can be seen on her collar.
Suggested correction: Actually there is a bell on her collar you can see it when Kate is preparing the food for the dogs.