Continuity mistake: 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. (02:00:40)
Factual error: At the end of the movie, the Straus' are seen lying in each other's arms on their bed with water coming into the cabin under the closed door as the ship is sinking. This is not true, their cabin was on C deck, but his body was found in the following days of the sinking. For his body to get into the open water it would have had to float through a closed door, and up several flights of stairs. Historically, they refused to leave the ship, and were last seen sitting in deck chairs. They were there when the ship sank on the boat deck. Her body was never recovered.
Continuity mistake: When Jack is teaching Rose how to spit, then gets caught by some ladies, he has a glob of spit on the far upper right side of his chin, then the shot switches and it is now on bottom middle and a little to the left of his chin. (00:52:25)
Continuity mistake: When Jack is playing poker in the beginning of the movie with the Swedish guys and Fabrizio we can see a short shot of his cards. He then takes another card and wins by having a full house. However, there was no way to get a full house with the cards he had by just drawing one more card. (00:22:50)
Factual error: A point is made in the movie, and it is well known, that the water temperature of the ocean where the Titanic sank is near freezing, and at the end after it sinks, the people in the water only last a few minutes before going into an unconscious stupor and then dying. but on the boat, as it is taking on water while it is sinking, Jack and Rose are running around in this freezing water for what seems about 30 minutes with no apparent ill effects. The water could not have been heated substantially, and they simply could not have lasted nearly as long as they did running around in this water as the movie showed without slipping into unconsciousness. (02:38:30)
Factual error: Rose turned left after exiting the elevator during the search for Jack during the sinking. In the real Titanic, there was a wall to the left of the elevator in E Deck. In addition, going left from the elevators would take her to the port side of the ship, but the corridor outside the cabin where Jack is is on the starboard side. (01:53:40)
Continuity mistake: When Jack and Rose are running through the dining room, both of them are completely dry and running up. After Cal tells Lovejoy he'll give him the diamond if he gets it back, we cut back to Jack and Rose and both of them are soaking wet, most noticeably Jack. (02:13:15)
Continuity mistake: After Cal throws Rose's cigarette away, she lowers her hand. Then there's a very brief angle on Molly Brown where Rose is lowering her hand again up to a point where it disappears offscreen. Then a millisecond later it cuts back to Rose and her hand is magically raised and still, no sign of her lowering it, and shortly after she lowers it while Cal extinguishes the cigarette and she places her index finger on the holder. Close-up on Rose and her fingers are in the previous position and she is extending her index finger again to hide the holder. So there's actually 2 mistakes in a lapse of 3 seconds. (00:32:10)