Continuity mistake: In the office with Q there is smoke coming from his pipe, when the shot next goes to Bond, there is no smoke at all. (00:12:15)
Revealing mistake: When Bond fights Quarrel and Pussfeller at the back of restaurant we can see that Pussfeller is replaced by a stunt double. (00:28:50)
Continuity mistake: When Honey is with Bond on the beach, she is holding two shells by her chest and lowers them when she is talking to him. But when the camera angle changes to behind Honey in the next shot, she is now holding the shells by her chest again. (01:01:45)
Continuity mistake: When Bond leaves the hotel to go to Governor's House he has no pocket square. At Governor's House he has his pocket square. Then in the next scene at professor Dent's, the pocket square is gone again. (00:25:30)
Other mistake: In the opening credits, Eric Rogers' surname is spelled as "Rodgers." (00:02:20)
Continuity mistake: The car chase that ends with the quip, "they were on their way to a funeral." During this car chase, you can see both cars coming round the same bend not just once, but several times. In between, there are close-up interior shots of Bond too. But three of the longshots are all from the same curve.
Revealing mistake: After Bond attaches the silencer to his gun, the next shot is of Professor Dent approaching the house at nighttime. However, the shot is the same shot from earlier of Bond approaching the house during the day. It has simply been mirrored and darkened to hide this.
Audio problem: During the opening credits (while it says: "assistant director") you can briefly hear the next bit of music start 12 seconds too soon - there are a couple of notes from "three blind mice" starting to fade in from the percussion music. But more time was needed, so the last 12 second of the percussion number are repeated. A slightly clumsy edit to cover the credits running longer than planned (best heared with headphones).
Factual error: When Bond and Honey are machine-gunned from the boat it is a Bren gun, but the magazine appears to be the wrong way round and faces backwards.
Plot hole: When the receptionist is showing Bond and Honey their rooms she opens the closet with clothes for Honey and says they just got their sizes the night before. How? Dr. No's people didn't know about Honey at all until she showed up with Bond, and they weren't even seen together until they were found in the swamp just several minutes before. (01:19:50)
Revealing mistake: Bond, Quarrel, and Honey are supposed to be walking through a saltwater river and yet none of them seem to react when coming out of the water with their eyes open so obviously it's fresh water used in the river. (01:15:10)
Other mistake: In Strangways' house, Bond picks up a framed picture. Just as the other person comes into the shot the image skips. (00:23:30)
Revealing mistake: The second car chase is made with the help from a greenscreen. The car's movements as seen on the background doesn't always correspond with Bond's steering and the following car is sometimes too close to the screen. (00:48:10)
Continuity mistake: When Honey is telling Bond that her shells could be sold for $50 in Miami, not only does the background appear to be the wrong section of the beach (it looks like the area up where her boat is stashed, not down on the sand bar) but at the bottom of the screen, some kind of buoy or flotation device bobs up on the water just behind Ursula Andress. A couple shots later, however, when they're running along the beach, the whole area is completely clear. (01:04:35)