Character mistake: After being asked in class, Max refers to what he does as a "vivisection of a once-living organism", which in itself is a contradiction because vivisections are performed on living organisms. What Max does is called dissection, or more specifically autopsy, because he does it to determine the cause of death.
Revealing mistake: When the gunman are shooting at McGarrett and the barber shop at the beginning of the episode, the head gunman is firing his weapon without his finger even being on a trigger. (00:07:00)
Lehu a Lehu - S6-E2
Visible crew/equipment: Danny is supposed to be looking for the suspect in the woods by himself and you can see another person on the top right hand side of the frame. The crew member looks as if he knows he is in the way and slowly backs away. (00:35:15)
Ua 'o'oloku ke anu I na mauna - S6-E3
Other mistake: The victim has been dead for six weeks, but when Steve and Lou enter his home, the printer is still printing bills. (00:19:35)
Continuity mistake: When Jerry is on the video call with Kono, he is wearing white makeup with red around his eyes, but when the shot shows him and the phlebotomist in the room, the makeup is gone.
Character mistake: Neil is looking over the model of the USS Enterprise close-up in Steve's office. The island structure on the flight deck is backwards.
Continuity mistake: The Russian spy Anna Novick picks up Dalton in a Silver sedan and continues into a shootout. The Sedan's identifying badge (Hyundai) switches between being present and not, throughout the entire scene. (00:23:50 - 00:27:25)
Factual error: In episode 17, Danny's Camaro is subjected to a number of bursts from a mini-gun, riddling it from stem to stern. In episode 18, Danny's daughter mentions that he had just had it repaired. There is no way an insurance company would not total that vehicle, since it would require replacing or using "Bondo" on virtually every body panel, not to mention mechanical repairs.
No ke ali'i wahine a me ka 'aina - S7-E2
Factual error: Five-0 brings up a map of all nuclear power plants in Western Europe that is completely inaccurate - most of the trefoil markers in Great Britain are placed nowhere near nuclear installations, and has 3 in Ireland (which doesn't have any nuclear reactors).
Ka makuahine a me ke keikikane - S7-E7
Continuity mistake: About to leave Doris' cell, Steve slings his backpack over his shoulder. 10 seconds later he does it again.
Ka makuahine a me ke keikikane - S7-E7
Other mistake: Halfway through the episode there's a drone view with the caption "RABAT MOROCCO". The clip is run backwards, with cars and people moving backwards, and smoke disappearing into a chimney.
Ka makuahine a me ke keikikane - S7-E7
Continuity mistake: Near the start Lynn goes to get more wine, carrying her wineglass. Switch to Steve sitting alone at the table - with Lynn's glass at her plate.
Factual error: During the show, they flash back to November 1963 and have Don Ho in a nightclub performing "Tiny Bubbles." The problem is Don Ho didn't release that song until 1966.
Character mistake: In episode 6-6 Steve explains to Danny that a 'klick' means a kilometre, 0.62 of mile, to which Danny replies: "Oh, thank you, G.I. Jerk, for the pedantic, uh I know what a klick is." In this episode, when Steve again uses the term 'klick', Danny replies: "You know, no-one can understand you when you say stupid things like klicks.", which prompts Kono and Chin to give the exact same explanation as Steve did in season 6.
He Kaha Lu'u Ke Ala, Mai Ho'okolo Aku - S8-E8
Continuity mistake: When the lab tech is talking about the plane part, she places a Surface Dial on the screen. Throughout the entire scene the Dial keeps moving around between instant cuts, sometimes more towards the right edge, sometimes more towards the center. In one shot it's right at the bottom edge, then in the very next shot it's further up the screen. And shortly afterwards, when the lab tech says "they're too precise", it's off the screen entirely and lying on the desk.
I Ka Wa Ma Mua, I Ka Wa Ma Hope - S8-E10
Factual error: If you put explosives on drywall it will obliterate it, not put a small hole in it.
Continuity mistake: When Jessie is being chased by Steve, she is wearing trainers (you can see the Nike logo on the side), but when she is in the interrogation room, she is wearing ankle boots.
Continuity mistake: Steve chases Jesse into a building. She opens a heavy door to the outside, slowing her down, and as she goes through he's about 10 feet behind her. We then cut to her running along a walkway and he's somehow dropped back another 20 feet.
He Lokomaika'i Ka Manu O Kaiona - S8-E20
Visible crew/equipment: You can see a crew member below Junior while he is trying to climb the side of a cliff. (00:18:30)
Mimiki Ke Kai, Ahuwale Ka Papa Leho - S9-E3
Continuity mistake: At the start, Meaghan Rath winds down her window and leans out to yell at the guy behind her. Leans back in, we cut to a shot outside the car and her window is instantly up.
Chosen answer: They are Junior's SEAL buddies.