Continuity: In "Where's Gary?" the length of the paddle ball string that SpongeBob uses seems to vary in certain shots. While the length is somewhat subjective one shot that is more conclusive is when Patrick finds Spongebob lying on the floor. The string on the paddle ball is fairly short. When the two get up to get a glass of milk, the string is now a lot longer.

Plot hole: Ep 3-21 Spongebob Meets The Strangler / Pranks A Lot: When the invisible Spongebob and Patrick scare Sandy, they are using a sheet to appear as "ghosts". However, the form of the sheet reveals that they don't have their helmet bowls on. How could they survive in the treedome that time? They sounded fine, not dehydrated.

Continuity: In some episodes, SpongeBob's house is apparently an actual pineapple (e.g. "Home Sweet Pineapple"), but in other episodes, it is apparently made of wood like in "Opposite Day", when they tear down the house and rebuild it.

Continuity: In the episode "F.U.N", the chum bucket is not across the road from the Krusty Krab, but in every other episode it is.

Plot hole: 3-21: Spongebob Meets The Strangler / Pranks A Lot, in "Pranks A Lot", Patrick and SpongeBob scare Sandy. When Sandy runs, gets into her rocket and flies away. When she moved bubbles appeared meaning there's water in her tree house. There's no water in there in other episodes because she's a land animal and breathes air.

Continuity: In "Pranks-A-Lot" when Sandy flies out of her dome in an escape pod to Texas, she leaves a big hole on top of her dome. In the next shot, it's gone. Very noticeable mistake.

Continuity: The Krusty Krab kitchen sometimes has deep fryers, and sometimes it doesn't. When it does, the fryers change locations in the room between episodes.

Continuity: REAL 3-18: Plankton's Army (aka Plankton's Last Stand) / Missing Identity: When the screen splits into 4, the last 2 events are not in chronological order. That is, they are not in the same order as they always have been.

Continuity: The road to the Krusty Krab changes depending on the episode. Like in "Your Shoe's Untied" it is a crossroad, but in "Pickles" it's just a road going to the side.

Continuity: In "Spongebob Meets The Strangler" when The Strangler and Spongebob arrive at the pineapple, look at the door: there is no doormat below it, but a couple minutes later Spongebob pulls a key out from under the doormat that was not there before.

Continuity: Throughout the whole series there was never a tree in Squidward's front yard. But in episodes like Christmas Who and The Snowball Effect there is a tree in the middle of Spongebob and Squidward's houses.

Other: In "Spongebob Meets The Strangler" when that fish holds up Spongebob's dry cleaning at the supermarket, it looks like he is holding it up with a coathanger because his hand is up in the air, but you can easily see nothing is holding it up. It's just floating up in the air.

Continuity: In the episode "Missing Identity", when Spongebob is talking to Patrick about saying "hi" to him the first time, Squidward's house is gone.

Continuity: In the Season 4 episode "Selling Out", at the end, all the customers leave the Krusty Krab. But when the Krusty Krab floods, the place is packed with customers.

Continuity: On "One Krab's Trash", when Mr. Krabs draws a ghost on a sheet of paper, it shows before it goes into Spongebob's rooms that there's only writing on one side (i.e. the ghost) and when it goes into his room, a shopping list is on the back.

Continuity: In episode 3-21, Spongebob Meets The Strangler / Pranks A Lot, in "Pranks A Lot": SpongeBob and Patrick are going to burn Mr. Krab's dollar, so he throws water on them and they become visible. Patrick is holding Mr. Krab's dollar. When he says "We're visible again", and he and SpongeBob start to scream, the dollar completely disappears.

Continuity: In "Sing a Song of Patrick" in season 4, Patrick creates his own song and listens to it with Spongebob in his pineapple. And at the end of the song the pineapple melts and the stereo falls on top of them and not the pineapple. But when they get up, the busted stereo disappears and the pineapple is on top of them.

Continuity: For the whole first season, Patrick's eyebrows are sideways "M"s, but in all other seasons, they're "Z"s.

Continuity: In "Bubblestand" after Squidward blows the huge bubble, he tells Spongebob and Patrick that the ability to blow bubbles is in his genes. If you look at the position of the bubblestand sign, the sign is facing the direction Squidward is talking. The sign had always been facing the street, which means that Squidward was actually talking towards the street, when Spongebob and Patrick are actually to his right.

Continuity: When Spongebob first shows the Patrick the technique for bubble-blowing, there are two red corals in the background - one on his right and one on his left. Later, when he shows Squidward the technique the red coral on the left side of the screen disappears.