In the cafeteria scene following Doc's "accident", Frank's food tray contains a whole potato. After the conversation with the warden it is in pieces.
When Wolf goes at Frank Morris with a knife in the yard the fight scene shows Wolfs hat mysteriously disappearing and then reappearing.
When at the warden's briefing with Morris, the warden drops his nail clipper into the dish with another nail clipper present. At this point they both are closed. At the next shot of the dish after Morris removed one nail clipper, the remaining clipper is now all of a sudden open.
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.
When 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.
Morris and the Anglins are shown blowing up their raft with their mouths. In reality they had turned a small concertina into a makeshift bellows, which they used to inflate the raft.
In the film, Frank Morris and the Anglins swim away from the island using what looks like just a large flotation device, when, in real life, the men constructed an actual 4 person raft complete with paddles.
The film makes it appear as though only Frank Morris, the Anglins, and Charlie Butts (Allen West) were involved in the escape. In reality, several prisoners, in interviews conducted over the years, said that they knew about the escape plan and helped the 4 men acquire the materials and supplies needed for the escape.
Contrary to how it is depicted in this film, the Anglin brothers were not sent to Alcatraz at the same time. John Anglin arrived at Alcatraz on October 24th 1960 and Clarence Anglin arrived on January 16th 1961.
The pictures first seen hanging on the warden's wall are President Dwight D. Eisenhower (in middle), FBI director J. Edgar Hoover (on left) and Attorney General William P. Rogers (on right). Later (due to the presidency change) John F. Kennedy's photo is in place of Eisenhower's --but Rogers' photo is still seen hanging, the Attorney General in Kennedy's administration was (his brother) Robert F. Kennedy.
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.
Some of the prisoners in the shower are evidently tanned, such as after a seaside holiday. This seems very unrealistic, as they all are long term convicts.
At the start of the movie when Frank is walking with the guards from the car to the boat he is briefly seen wearing a hat which quickly is blown off his head by the wind but this is ignored by the guards and they continue walking to the boat.
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.
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.
Prisoners are shown seated at long, picnic-table style dining room setting. However, some time prior to the escape, the arrangement was changed to 4 person tables.
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.
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.
When Morris walks into the warden's office, you can see the outline of something in his rear pocket, possibly a lighter, that he wouldn't be allowed to have or carry.
In the warden's 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.
When Morris meets the warden on his arrival, the warden states that no newspapers, or magazines carrying news, are issued to the prisoners. However, Morris' library duties later include delivering issues of The Saturday Evening Post and Ebony, publications containing news items in each issue.
In his opening monologue, the warden mentions his predecessors, including a previous warden named Johnson. He's presumably referring to James A. Johnston (note the T in his last name, which the warden does not pronounce), who was the first warden of Alcatraz, presiding over its opening in 1934 and retiring in 1948.