Anachronisms: The Mount Sutro Tower (breaking ground in 1971 and completed in 1972) is pictured in the movie's opening sequence while at the same time on-screen text indicates the plot year to be 1960.
Continuity: The cell occupied by Frank's blockmate Charlie Butts.
Continuity: Frank Morris' bed is on the right side of the cell in some scenes, and on the left in others.
Revealing mistakes: In the beginning, where Frank Morris is being escorted through Alcatraz, we see him from behind, naked. We also see him being escorted by the guards from within a cell, and very brief, you can see that he is wearing a white towel around his hips. In the next shot, he is seen naked from behind again. Finally when being put in his cell, he is once again wearing a towel.
Continuity: The position of the Warden's hand while he is holding the flower in the last scene.
Continuity: Position of Butts' arms change as he squeezes through the vent hole of his cell during the escape sequence.
Boom mic visible: In the wardens office, when Morris is being briefed by the warden, the camera pulls back to (accidentally) reveal the large hole in the office ceiling. At this point the boom is quite visible.
Anachronisms: When Frank Morris smuggles the metal wedge through the detector, there is an oscilloscope connected to the detector loop that was not made until the 1970s.
Revealing mistakes: Frank Morris sticks a mirror out of his cell to spot the guard, but the angle he's holding it at is for the benefit of the camera. He can only see the back of the mirror.
Anachronisms: Coast Guard cutter searching for escapees has a red diagonal stripe painted on the hull near the bow. This stripe was not adopted by the Coast Guard until 1967.
Continuity: In the cafeteria scene following Docs "accident", Clint's food tray contains a whole potato. After the conversation with the warden it is in pieces.
Revealing mistakes: When Doc chops his fingers off, a brief close-up on the severed hand and fingers reveal that they are clearly made of prosthetics, and there are no fingernails on the rubber parts.
Anachronisms: On the boat ride over to the prison from San Francisco a radar unit can be seen spinning on top of the boat. That type of radar transponder wasn't developed until the mid 1970s. According to the information on screen, this took place in 1960.
Continuity: In the scene where Doc is painting in the prison yard, the spots of wet paint on the left-hand side of the canvas change. Doc and Frank are having a conversation - the shots showing Frank speaking do not show the canvas for the most part, while the ones that show Doc speaking do. The wet spots increase and decrease in size and number every time the canvas is shown.