Visible crew/equipment: When Jack and Rose are running away from Cal to the first class dining room, if you look at the glass you can see a black screen, a light, and a crewman.

Continuity: At the part when Jack or Rose (I can't tell which) wipes their hand on the fogged up window, they show it again in the next shot and you can definitely tell it's a completely different handprint.

Deliberate "mistake": When Jack draws Rose the hand that is shown in close-up is much too old to be his. [It's James Cameron's hand - still a mistake, but there's why.]

Continuity: When Jack is asking Rose to dance after dancing with the little girl "Cora", you will notice that Jack's hair is down when first asking her and when the camera goes to Rose and then back to Jack that it is back up with, all nice and neat.

Continuity: Right before dinner, Jack and Rose are talking to the Astors, and Molly comes up from behind them, asking Jack to escort her to dinner as well. In the next scene, when Cal calls back to Rose, Molly is still walking up to them.

Continuity: When Rose is lying on the piece of board and she is trying to wake Jack by shaking his hands and such, there is some frozen stuff under Jacks nose. The scene cuts back to Rose and when we go back to Jack the ice isn't there. Then the scene cuts back to Rose and the next time we see Jack he has it on his face again.

Continuity: In the scene where one boat drives back to search for survivors you can see the lightspot of one lamp turn around faster than the man who hold this lamp, so you know that the lightspot is not from the lamp of this man but from a studio lamp. The man sees that himself and turns around very quickly to hold the speed of the spotlight.

Deliberate "mistake": In the scene at the start of the movie with the "authentic" piece of film, you can see a girl with a hat waving to the people at the ground. When the ship is leaving port in the film, she and others are in the same positions, only in reverse, because the first "authentic" shot is the same shot, only reversed.

Factual error: When Rose, Jack and his friends come up to the boat deck while the ship is sinking, they ascend using the second class staircase and its exit on the deck. When Jack lets go of the door it is able to hit the side of the deckhouse. On the actual Titanic there were walls on the bow side of each door, which supported an overhang above the entrance. This is not included in many scenes in the movie.

Continuity: In the dinner scene, just after Jack says, "Never did like it much", Cal starts laughing, but in the next shot he has a straight face and is chewing.

Revealing: When Rose and Jack are on the back of the sinking ship, when she looks to her left at the woman next to her, she has almost no makeup on, but when she turns her head back to Jack, she has fresh makeup on.

Continuity: When Rose approaches the stern railing to climb over it casts a very clear moonlight shadow on the deck which is not there in all other shots of this scene.

Factual error: When Jack, and Rose were trying to escape the rising water they were trapped by a locked gate. Jack and the crowd pulled up a bolted down bench to use as a battering ram. When they pulled the bench loose they showed a close up of the wooden floor shattering. The wood was pressed fiber board which would never be used as ship decking, not to mention, pressed fiber board wasn't invented until decades later.

Continuity: In the scene where Rose breaks Jack's handcuffs, you can visibly see the stunt person not wearing suspenders as Jack does. This is an inter cut shot between the raising of the ax and the striking of the cuffs. Leonardo's stunt double is noticeable in other shots throughout the film.

Revealing: When Cal shoots at Rose and Jack he hits a decorative wooden structure on top of a banister. When the piece falls apart you can see that it has been neatly cut in the middle, and you also see the explosive device that blew it apart.

Factual error: The Master-at-Arms office, where Jack is handcuffed, was in actuality an inside cabin and had no portholes at all.

Continuity: When the camera pulls back through the pub window to reveal the card players, if you look carefully in the background you will see a Steam Engine on the dock. Unfortunately the computer generated loco is clearly American as it has two domes, something NEVER seen on British locos. It also is shunting what looks like a carriage - again, this is also American. Carriages were rarely seen at docks, except if a train was connecting to a ship, and this was not common until the 1920s. 

Continuity: In the beginning, when the safe is being opened, there's a close-up of the grinding wheel digging into the metal. In the next shot the crewman who does the job is only kneeling down, while the grinding sound is already there.

Continuity: After Rose cuts Jack's handcuffs with the axe there is no chain left in between the two wrist cuffs. There was enough room between his hands to stretch them across the pipe so there must have been at least a few inches of chain. Surely there would have been some chain links left on one side or the other depending on where she cut it.

Continuity: When Andrews is on the deck and the crew are lowering the boats, he walks down a staircase, (not the grand) you see a vent, used to bring air into the ship. But all of the vents had motors, and you can see this one doesn't; even though it is still there on the wreck.