Revealing mistake: In this scene, at the end of the film when Jack and Rose are hanging onto the railing, you can see the ship split in half, but when it drops, if you watch closely on the right side of the screen, you can see that the entire ship is still intact, the lifeboat cranes are visible all the way down the top of the ship. (02:35:10)
Continuity mistake: When Captain Smith says to Mr. Murdoch "let's stretch her legs" the light comes from the port side. When Murdoch enters the bridge the light comes from starboard. (00:29:00)
Factual error: Jack (Leonardo DiCaprio) was handcuffed with old English Hiatt's Darby Handcuffs (type 104). This is historically correct. But the key for these handcuffs identifies them as modern reproductions, because it had a flat top and was "checkered". The old keys had an oval and smooth (only marked with "Hiatt" and a number) top. The handcuffs used in the film were not from 1912. (01:47:50)
Audio problem: When the leader of the orchestra suggest to play "Orpheus", the music starts later than the musicians actually begin playing their instruments. (02:07:00)

Continuity mistake: In the scene where Jack and Rose are on the third class level partying with the other people in third class. When Jack hands Rose a glass of beer, how she holds the glass differs between shots. (01:06:20)
Continuity mistake: When Jack holds the diamond his nails are clean and perfect. When he starts to draw they are ugly cut and dirty, revealing they're somebody else's hands (later known to be director James Cameron's). (01:21:00 - 01:23:30)
Continuity mistake: As Rose shows the men she can rise up on her toes, from the front she has a cigarette in the first three fingers of her right hand. In the next shot her right hand is seen under her left arm and she has no cigarette. When she falls back into Jack's arms the cigarette is back in her right hand. (01:06:50)

Continuity mistake: During the first meal on the Titanic (the one where Cal plucks Rose's cigarette from the holder) the stone on Rose's necklace changes between almost disappearing in her dress and about two inches above. (00:33:10)
Deliberate mistake: Even though the movie uses the correct number of rockets, the timing is awful. The last rocket was fired at 1:40 AM at the latest. In the movie, the last rocket is fired when the last boat to be lowered on the davits leaves (the one Rose gets, and jumps off of). This would make it 2:05 in James Cameron's Titanic time. It was probably changed to add more drama to that heart-throbbing scene... (02:18:30)
Factual error: All deep sea submersibles that travel to depths of two or three miles fall to the ocean floor with no power on. At the start of the film, you see MIR1 and MIR2 pan past the camera with all their lights on. The lights should be off to conserve electrical power. The journey to the sea bed takes two and a half hours. (00:02:00)
Deliberate mistake: When Jack and Rose are adrift in the ocean, the stars behind them are not the right ones for that time and date. In fact, it's not any sky ever seen on Earth. The right half of the sky is a mirror image of the left half. The fimmakers deliberately positioned the stars to form the shape of the pendant 'Heart of the Ocean.' (02:46:00)
Continuity mistake: When Jack cries he's king of the world he raises his arms pointing in an 11-12 o'clock direction. A frame later, from a different angle, they're in a 9-10 o'clock direction. (00:31:00)
Factual error: When the captain declares to Bruce Ismay that the last boilers have been lighted, it's only half true. Sunday morning, the last "regular" boilers were lighted to reach a total of 24 out of 29. The five boilers of the auxiliary boiler room number one are not in operation yet. The day after, weather permitting, it was planned to light them on for a few hours to see if the Titanic had something in the ball. (01:13:00)
Visible crew/equipment: When Jack and Rose are going back to the sitting room to tell Cal and Ruth about the bad news, you can see a crew member reflected on the wall over by the door. (01:41:00)
Continuity mistake: Close to the end of the film when lots of people are trying to free the lifeboats from the ropes, you can see Cal, climb up a black wire and stand on the side of a half turned lifeboat, but if you watch closely in the following shot, you can see that Cal is still climbing up the black wire. (02:27:55)
Continuity mistake: On the day after Rose got the diamond she and Jack talk a walk on the deck. From the light on the deck you can tell that the sun is still fairly high up. When the camera angle changes and we see them from behind the deck is in the dark, and the sun is falling in almost horizontal. When they sit down to look at Jack's drawings the sun is higher again. (00:46:15 - 00:49:10)
Factual error: On the real Titanic the first set of davits were cranked back in to lower the lifeboat Cal is in, not the second set. One of the davits that should have been cranked back in is still on the real Titanic in the position ready for picking up the lifeboat to lower it. (02:25:40 - 02:34:45)
Continuity mistake: When Cal gives Rose the diamond her front hair changes from shot to shot, most drastically when she says "good gracious." (00:44:30)
Factual error: Early in the film Jack smokes hand-rolled cigarettes. When he is smoking on the stern deck before Rose is thinking about jumping, he is smoking a mass-produced filter cigarette. Filters in cigarettes didn't exist in 1912. (00:36:05)
Continuity mistake: In the scene where Jack is handcuffed water starts running into the room the desk. At that moment the desk, which had been out of reach before, is moved closer to Jack and standing diagonally, so that Jack can climb on it. This happens before things get moved around by water or gravity. (01:54:45)