Continuity mistake: When James Bond is fighting underwater with an opponent, the opponent rips off James' diving mask (which is blue). Then James rips another mask off another opponent who is lying dead on the ocean floor. This dead opponent's mask is black. James puts on the black mask and then he turns around and the mask is blue again.
Revealing mistake: In the scene where Bond is trapped in Largo's shark-infested pool, he uses his mini air tank to breathe. In most of the subsequent shots, look closely at the actor's face: it looks a lot more like a stuntman than Sean Connery.
Other mistake: During the sequence where Bond flees the baddies during the carnival, it becomes clear that the locals made their own outfits. For a few seconds, we see a group with headpieces that read "007" - so much for "secret" agent. To add a bit of humour to the moment, a dog can be seen urinating against the passing parade.
Revealing mistake: When James Bond and Felix have found the missing plane, look at the colour of the water as the helicopter lands, it is evident that is landing in shallow water, (they are supposed to be in much deeper water with sharks swimming below them) you can see the sand below. If the helicopter had landed on deeper water, the water colour would be dark blue.
Revealing mistake: When Bond hits the fire alarm in the spa with his elbow you can see the padding on his elbow to protect against the blow.
Plot hole: When Angelo sets the Vulcan down in the sea, he blows the canopy and extends the landing gear. As the plane settles, he attempts to release his harness, then has his air line cut by Largo. He futilely beats on the harness release, when all he had to do was pull the face curtain handles to trigger the ejection seat, which would not only blow him clear of the plane, but would separate him from the seat itself. Having trained for two years, for this specific mission, he would undoubtedly be familiar with ejection procedures.
Continuity mistake: Just after James Bond and Domino leave the gaming table to sit at a table to order, the two views of her back shows that she is holding a cigarette in her right hand that is not lit, but in the two views facing her the cigarette is lit with smoke.
Continuity mistake: When Bond and Domino are walking along the beach in shallow water, Domino stands on a poison quill spine with her right foot. But when is Bond sucking the poison out, he does so from her left foot, because Domino displays the injured foot as the left one.
Other mistake: When Bond and that girl are floating at the end right after the boat crashed, the bottom of the ocean looks very shallow and very much like the bottom of a pool.
Revealing mistake: When the plane being piloted by the traitor crashes into the water, during the time while it's skidding across the surface and especially when it stops, you can see a large black wire attached to the middle of it and going into the "sky".
Factual error: Bond and Leiter are in the helicopter and as Bond tells Leiter to get the military personnel to show up for the show-down, he makes reference to "Miami Beach and Orlando Beach". Seeing as how Orlando, Florida is about 50+ miles inland, there is no such place as 'Orlando Beach'.
Revealing mistake: When Bond goes into the hotel room and finds the girl in the bath, he gives her a pair of gold shoes. She gets out of the bath with the towel wrapped around her. However, when you look in the mirror, you can see that she has a pair of white pants on.
Visible crew/equipment: When Bond is at the spa he breaks into Lippes' apartment and as he gets to the front door, a shadow moves across the wall next to Bond going in the opposite direction. It's not Bonds' as his is clear on the wall already, I assume a crewmember.