Goof (continuity error): In some earlier episodes, McGarrett can be seen leaving his headquarters in a 1967 Mercury 2 door sedan, when he reaches his destination, he's driving a 1968 Mercury 4 door sedan.
Goof (continuity error): After the original 1968 Mercury was retired, and replaced with a '74 Marquis Brougham 4-door hardtop, some stock footage was used of the '68 passing or in traffic.
Goof (continuity error): In the episode "Hook man" McGarrett is chasing a suspect who is driving a 1968 Ford Mustang. When the police retrieve the car from the bay, it has become a 1966 Ford Mustang.
Goof (continuity error): In "The Capsule Kidnapping", the kidnappers are attempting to flee from McGarrett in a private airplane. When they board the plane and while McGarrett's chasing them around on the taxiways of the airport, the plane is a twin engine propeller aircraft. When it becomes airborne, the aircraft shown is a twin engine jet.
Goof (continuity error): When intelligence chief Brent bends over the man McGarret shot, he immediately removes the knife from the man's hand. The scene shifts to McGarret on the phone, then back to Brent, who is shown removing the knife from the dead man's hand again.
Goof (revealing mistake): When McGarrett is being followed by the Intelligence guy, the image in his rear view mirror is not reversed.
Goof (revealing mistake): When McGarrett is being followed by the same sedan, he calls for a HPD ambush on the police radio, but he never takes his thumb off the talk button, even when dispatch is replying. Since radios are one way devices, it is necessary to release the talk button in order to hear the other party.
Goof (errors made by characters, possibly deliberate errors by the filmmakers): At about 45 minutes in, Chin Ho reports, "Same green convertible" but it is really a red convertible.
Goof (errors in geography): After Victor Reese walks past Joyce Weber on the cruise ship, which was shown just previously as being at sea, you can see over Joyce Weber's shoulder that they are sitting in port with a moored ship and dock crane in the background.
Goof (continuity error): When McGarrett is briefing Joyce on her assignment in back of the car, they are being followed by a blue 1968 Ford LTD. Moments later it has changed to a black 1966 Ford Galaxie.
Goof (revealing mistake): After 41 minutes of the show, the phone rings in McGarrett's office. He answers the phone, but it continues to ring for several seconds more.
Goof (continuity error): For most of this episode, 'Richardo Montalban''s character is referred to as Mr. Namura, not Mr. Tokara, although that is said to be his real name later on.
Goof (factual errors): The screenwriter seems to have confused the Bushido (samurai) with the ninja (ninjitsu). The Samurai were not a secret society.
Goof (revealing mistake): The close-up of Thad's gun when Ann picks it up from the floor shows it to be a short barrel S&W .38 with blue finish, the exact type carried by Five-0. When the gun is found by Five-0 and identified as the one wielded by Thad, it is a .32 with bright finish.
Goof (continuity error): After McGarrett leaves the gambling raid, his car is a 2 door. While driving to the dock, it becomes a 4 door.
Goof (crew or equipment visible): This episode opens with a high speed police pursuit in a fairly remote area, which was filmed either late in the afternoon or early in the morning. During one shot of the speeding vehicles shot from a distance, the silhouette of the film crew can clearly be seen on the low-angle shadows cast on the road where the vehicles are being driven.
Goof (continuity error): Through out the episode Jerry Fielding's unit is identified as the 25th Infantry Division. Fielding and his buddy from Nam are clearly uniformed as paratroopers in the 101st Airborne.
Goof (continuity error): When McGarrett leaves headquarters he's driving a 2-door Mercury but when he arrives at the Lo murder scene he's driving a 4-door.
Goof (miscellaneous): Throughout the episode Johnny Crawford's character is referred to as a Private. He wears such an insignia. In the closing credits, he is listed as a Corporal. Is this a mistake or a message that he was promoted to Corporal just after the episode ended?
Goof (continuity error): Episode "Deathwatch", the young Assistant Prosecuting Attorney shines his door's name plate which says Charles Cadison. In the closing credits, he and his wife's names are listed as Kadison.
Goof (errors made by characters, possibly deliberate errors by the filmmakers): Danno kicks open a door looking for the box man, after checking to see if it is latched. When the door swings open, the lock is unlocked (bolt retracted), and there are no other latches.
Goof (errors made by characters, possibly deliberate errors by the filmmakers): When Attorney Cadison leaves his car he is not wearing a wedding ring.
Goof (continuity error): Harry Cardonis lends his car to his girlfriend. Upon turning on the ignition, the car explodes, but you can see the car is intact, and the paint isn't even damaged, although it is enveloped in smoke.
Goof (continuity error): While going over to the lift outside the hospital, Lt. Kealoha holsters his gun twice.
Goof (errors made by characters, possibly deliberate errors by the filmmakers): McGarrett performs incorrect CPR on the patient.
Goof (crew or equipment visible): At the end, when the camera pans out with McGarrett holding Austin, you can see the shadow of the camera to the left off the doors and hall way wall.
Goof (factual errors): Col. Tyler, in describing an older generation infrared sensor says that "the noise to signal ratio is too low".
Goof (revealing mistake): The foil suits worn by Five-O while they search Fong's house are US military fire suits, not HAZMAT suits. The fire suits do not afford the same degree of protection against biological agents.
Goof (audio/visual unsynchronized): Every time McGarrett speaks the name of the ship, the dialogue doesn't follow his lip movements. The name of the ship may have had to be changed after the initial filming for some reason.
Goof (miscellaneous): In this episode, Gerald S. O'laughlin's character is named Charlie Swanson. In the closing credits, his name is Carl Swanson.