Goofs

In the very first scene, the room where Suzy and her brothers are playing is an attic room with sloped walls. When the shot changes to the exterior, it is a normal mid-level room with straight walls.

An overhead shot of the police station wagon driving across the island shows a smooth top and just the red light. In later shots, the station wagon has a rack on the top and a siren in front of the red light.

When Scout Master Ward exits his tent the morning after his troupe leaves to rescue Sam and Suzy his neckerchief is on/off between shots.

As Scout Master Ward is going to Sam's tent, the hole Sam has made is not visible from the outside.

When Scout Master Ward asks "Who's missing?", there are nine scouts at breakfast mess and one empty chair (at around 42 mins), but there are eleven scouts in Troop 55. In addition to Sam, Lazy Eye is also missing from the mess table. He reappears (at around 15 mins) when ten scouts and Scout Master Ward peer into Sam's tent.

When Cousin Ben is talking to Sam and Suzy as they walk through the camp, a marching scout extra in the background can be seen looking and waving at the camera.

When Scout Master Ward enters Sam's tent at Camp Ivanhoe, he discovers that it's empty and that Sam has left via a hole in the side of the tent. The hole is covered by a map, but it's taped to the inside of the tent. If Sam had actually left via the hole, he would have no way to stick the map to the side of the tent, and if he had left via the tent door - which was zipped with the zipper-pull on the inside - there would be no reason for the hole in the first place.

The sail position does not change when the yacht pushes of the pier and moor back. It is not possible during real sailing.

While Captain Sharp and Mr. Bishop are riding in the police car, the gear shift is in "Park".

The Island Police car is a 1968 Plymouth. The movie is set in 1965.

In the sailboat scene the sail itself has a Quantum Sails badge. Quantum wasn't founded until 1996.

When Sam and Suzy are writing letters to each other before their first meeting, the bedspread shown behind Sam features a '70s to '80s-style Formula 1 race car.

At the end of the film, the top of the chapel crushes a 1969 Volkswagen Beetle. The movie is set in 1965.

When Sam and Suzy are first found by the Khaki Scouts, the boy who tells Suzy that Sam is crazy has metal braces on. This type of metal braces wasn't introduced until the 1970s. The film is set in 1965.

When the audience is hearing the broadcast over the transistor radio, the close-up shot on the radio reveals that it is turned off.

The recording which contains "The Carnival of the Animals" and the "Young Person's Guide to the Orchestra", both conducted by Leonard Bernstein, is a 12-inch LP which plays at 33 1/3 RPM, not a single that plays at 45 RPM.

Camera shadows are visible in the lower right corner on scouts and the police chief while on the boat dock.

There are numerous inconsistencies between the map shown in the beginning of the movie during the narrator's introduction of New Penzance, and the two maps shown later in the movie when Troop 55 rows across the Cold-Water Strait and when Scoutmaster Ward sends a message to Fort Lebanon. The map in the beginning of the movie shows that there are no islands in Stone Cove, but the later maps do have an island; the size, shape, and position of Belgian Hours change in the later maps compared to the first map; Lily's Look-Out, Polish Prince, Treasured Indian Grip, and St. Jack Township are labeled farther east on the first map compared to the later maps. There are also many coastline inconsistencies between the first map and the later maps.

The pilot of the plane incorrectly says the word "five" as "fiver". In standard aviation phonetics--NATO alphabets--the number "nine" is pronounced "niner", to distinguish it from "five", which is pronounced as "fife".

Suzy's left-handed scissors are mentioned at least two times but after she stabs a scout with them, she's shown holding them in her right hand.

When ending the radio conversation, policeman says, "Over and out". This combination does not exist in standard radio communication protocol where only "out" is used to end the conversation (while "over" indicates passing the voice over to the other side).