Continuity mistake: Jerry's apartment in the first episode was on the fourth floor. Then in the next bunch of episodes it was 3A. It then changes to 5A for the remainder of the series.
Factual error: During the entire series, the view of Jerry's door from the hallway is of a flat wall with the door in line, yet from inside The Apartment, not only does the kitchen angle into the hallway, but Jerry's fridge is recessed into the wall. The wall behind it should be blocking the hallway completely.
Visible crew/equipment: After Jerry, Elaine, George and Kramer walk out of the orange stairwell, there is a shot as they come out the door. A car drives past. The crew is reflected in the window.
Continuity mistake: The private jet that The Limo pulls up to on the ground and the one that they show the gang on while flying are two different types of planes.
Continuity mistake: In the opening scene in the locker room, George's shoe goes from off his foot to on to off to on.
The Statue - S2-E6
Continuity mistake: In The Statue, George claims to have broken a statue that used to sit on his mantle. However, in season 6 episode 3 "The Pledge Drive", George states that he would be a completely different person if his parents had a mantle.
The Cigar Store Indian - S5-E10
Continuity mistake: George has sex in his parent's bed, explaining "My bed is too small." But in another episode, we see George's parents bedroom, and they sleep in separate twin beds, not a big bed.
Factual error: At several points during the case, the prosecutor introduces witnesses by saying "The state calls." Legally, Massachusetts is a Commonwealth, not a state, and that is how it is referred to in court. (See any episode of "Ally McBeal" or "The Practice.") However, even this would be incorrect here, as the episode makes it clear that the "Good Samaritan" law is a local Latham statute, not a Massachusetts law. In this case, "The people call." would be correct.
Continuity mistake: Towards the end of the episode, it transitions between the Yankee ball at night and "Susie's" wake which is during the day.
Continuity mistake: In this episode, George asks Russell if his last name contains a "y" and Russel answers that it doesn't. However, Russel is credited in this and subsequent episodes as "Russell Dalrymple."
The Red Dot - S3-E12
Continuity mistake: After Elaine unwraps her cashmere sweater, Kramer wraps the ribbon around his neck in a scarf-like way and then lies back on The Couch. In a long shot of The Apartment (as Elaine exits the bathroom), the ribbon is gone, but when it cuts to Kramer and he asks about The Red Dot (and for the rest of the scene), the ribbon is back.
Continuity mistake: Shot shows a DC-10. Next shot is the inside of a plane that is not a DC-10. Only one aisle. DC-10s have two aisles. (00:00:35)
The Hot Tub - S7-E5
Deliberate mistake: When Elaine comes home and doesn't find Sean Paul there, she runs to her neighbour across The Apartment. The neighbour opens the door and stands outside it then the door slowly closes behind him. Suddenly, the door opens again with a swoosh without anyone being there. Because the camera switches angle right after this, it is apparent it was opened to gain this shot or to at least permit it continuity wise. (00:16:40 - 00:17:10)
Other mistake: In the scene where Jerry, George, and Elaine are in the coffee shop and Kramer walks in with the dummy mailman with the bucket over his head, Kramer remarks how nobody entered the post office while he was outside protesting. Jerry remarks, "That is because it is Sunday." If that is true, how can the group be gathered at the coffee shop? There is a red sign by the entrance of the coffee shop showing the business hours, and the coffee shop is supposedly closed on Sunday.
Revealing mistake: When George puts down the hairdryer next to the picture of his "fiance", if you look at the bottom right of the screen, you will notice a blue flame most likely from a torch the crew used to create The Fire.
Continuity mistake: In the episode where Kramer becomes a ball-man, the episode ends with them at a tennis match. It shows a shot of the court, and no one is standing anywhere near the poles of the net. In the next shot, Kramer is crouched down next to the pole, ready to dive for the ball.
Plot hole: When George and Jerry are discussing The Rye bread scheme, George says Susan is working late that night, so she won't be around when he sneaks The Rye into the house. But when George reels The Rye in with the fishing pole, Susan is standing there with her parents, wearing her coat. When did she get home? She couldn't have entered through the front door, because Jerry was there tossing The Rye up to George. And since it's a New York City brownstone, there's no backdoor that's accessible. There's no logical explanation for her getting into the house to see George reeling in The Rye.
The Frogger - S9-E18
Factual error: Frogger machines kept scores, but they didn't keep the initials of the person who got the score.
Continuity mistake: Jerry is waiting for George to come into his apartment and he says to Elaine and Kramer, "my oldest friend is dating the governor", and then folds his arms. In the next shot, as George comes in, Jerry is suddenly holding a glass of juice - there was no time for this change to happen naturally.
