Continuity mistake: When Jack and Rose are being carried towards the locked gate by the water, we see the water and Rose hit the gate in the first long shot and then the camera changes to a close angle of the gate and Rose and the water have not reached the gate yet. (02:15:30)
Revealing mistake: You need to watch carefully for this as it's tricky to spot, but it is visible without the need of slow motion. When the steward calls for the gate to be unlocked to the third class passengers, the gate is already open and just pushed to a close. You can see the gate wobbling and separating around the lock area. Also as the gate is unlocked we see a key being pressed against the lock to unlock it. However the key doesn't actually engage with the lock, making it impossible to open it. (02:02:50)
Continuity mistake: When we see Rose at the start she says she doesn't know what all the fuss is about. As she says this she has her hand on her hat, but after the angle changes it isn't. (00:21:15)
Audio problem: In the poker scene, when Jack picks up a card from the deck, it makes a very loud and long noise. Much louder and longer than the movement of the card against the deck would justify. (00:23:15)
Revealing mistake: When the boat is totally slanted sideways and Rose encounters Andrews, note the glasses and stuff over the fireplace and behind Rose. They don't slide downwards or move a single inch, defying the law of gravity, revealing the camera trick. (02:21:00)
Factual error: During the sinking scene, Murdoch looks down the crew stairs on the starboard side, where water is entering from an open door on deck A. That door should have faced outward (starboard side) otherwise the door would have lead into cabin A7 and I don't think the occupant would have enjoyed that.
Continuity mistake: Cal checks his pocket watch when getting ready to board the Titanic. In one shot he has his walking stick raised. In the next shot it has vanished completely. (00:21:50)
Continuity mistake: After Rose breaks Jack's handcuffs they join some sailors to ram down a gate. A frame later, from the opposite angle, the gate's position is totally different. (02:03:10)
Continuity mistake: Rose is attempting to commit suicide and tells Jack to leave. When he says "No", his hair swaps from being all over his face to neatly combed, between shots. (00:38:15)
Continuity mistake: Inside the car, Jack places his hand on Rose's shoulder, but a frame later it's on her arm. (01:30:00)
Revealing mistake: Just after Rose spits in Cal's face and runs off to find Jack, the camera goes into the water to show Jack through one of the portholes. In the external shot, it shows that the porthole is a good distance under the water. However, just as Jack says "Hello? Help me" you can see the water dip below the top of the pothole a number of times as it sloshes about.
Factual error: The ribbons on Captain Smith's medals are incorrect. The ribbon on his Reserve Decoration should be plain green (it is green and red in the film) and that on his Transport Medal should be red and blue (it is blue and white in the film).
Continuity mistake: When Jack is manacled in the master at arms' cabin as it floods, the drawers from the left-hand side of the desk behind him are floating around in the water, then for a short shot are back in the desk and then floating around in the water again.
Continuity mistake: When Rose is hanging off the back of ship she first isn't holding the train of her gown then suddenly she is.
Visible crew/equipment: When old Rose is traveling in the helicopter at the beginning of the movie, the skids of the filming helicopter can be seen reflected in the window of the one Rose is in. (00:13:02)
Factual error: In the seen after the preacher finishes his dialogue; it shows the woman floating in the first class lounge with which is completely under water. But about a minute or so later after it shows the maid slide down the deck, the part of lounge that was supposed to be flooded is still above water. The lounge in just a bit forward of the 3rd funnel on A Deck which wasn't submerged until after the break up in the film. The light fixture is one deck down aft of the compass tower between funnel 2 and 3.
Factual error: When Rose's mother is having tea, all the women are wearing gloves as they have tea. This would never have happened as Edwardian ladies always removed their gloves and placed them in their laps under their napkins when they sat at a table, before eating or drinking anything so as not to soil them.
Continuity mistake: After Old Rose watches the taped images of the sunken Titanic, Lizzy puts her hand on her shoulder. Then she takes it off and moves away. When the angle changes her hand is still on Rose.
Continuity mistake: When old Rose grabs the dragonfly jewel she places her left finger under the broken wing. When the angle changes her finger is away and she is repeating the previous movement.
Continuity mistake: When Jack is talking to Rose for the first time, his hair is constantly changing position. (00:39:30)
