Jellyfishing / Plankton! - S1-E3
Continuity mistake: Spongebob crashes through Squidward's house, and his bedroom is on the bottom floor. But in "Shanghied" after Squidward exits the fly of doom, you can see his bedroom is on the top floor, as it is in other episodes.
Continuity mistake: 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 mistake: 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 mistake: In the episode "Missing Identity", when Spongebob is talking to Patrick about saying "hi" to him the first time, Squidward's house is gone.
Pressure / The Smoking Peanut - S2-E12
Continuity mistake: In "Pressure" right before they all jump on land Squidward has 6 legs, but when he gets on land he has 7 legs.
Bubblestand / Ripped Pants - S1-E1
Continuity mistake: 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.
Hall Monitor / Jellyfish Jam - S1-E7
Continuity mistake: When SpongeBob asks Squidward to play his clarinet better, he is wearing his night shirt which is purple, but in the next shot he is wearing his normal shirt which is brown.
Continuity mistake: When everybody comes to Squidward's house to persuade him to write a letter, you see that all the paper and pencils and bottles on the ground disappear.
The Great Snail Race / Mid-Life Crustacean - S3-E15
Continuity mistake: When Gary explodes or breaks down (or something like that), Snellie, Squidward's snail, rushes over to Gary. At first you see the track but the next shot (really quick) you don't see it.
Jellyfishing / Plankton! - S1-E3
Continuity mistake: In Plankton, when SpongeBob steps on Plankton, he steps on him with his left foot, except he pulls Plankton off of his right foot.
The Snowball Effect / One Krabs Trash - S3-E3
Continuity mistake: 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.
Selling Out/Funny Pants - S4-E5
Continuity mistake: In "Selling Out", at the end, all the customers leave the Krusty Krab. But when the Krusty Krab floods, the place is packed with customers.
Bubblestand / Ripped Pants - S1-E1
Continuity mistake: 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.
Grandma's Kisses / Squidville - S2-E9
Continuity mistake: When Squidward parks his bike next to the store, he goes inside, and when he goes outside, his bike is gone.
Valentine's Day / The Paper - S1-E16
Plot hole: When SpongeBob goes to Sandy's house, he blows a chocolate bubble with the shape of a heart. Sandy opens a little door and the heart comes in. But, if the heart enters, don't you think that water would have also entered?
Boating Buddies/The Krabby Kronicle - S6-E9
Other mistake: In "Krabby Kronicle," when the two scientists exit Sandy's air dome, there are bubbles trailing behind them.
No Weenies Allowed / Squilliam Returns - S3-E6
Continuity mistake: In "No Weenies Allowed", the gatekeeper in front of the sailor club has a tattoo on his front with a heart and MOM on it. Sandy rips it out and places it back upside down. It now shows an upside down heart with WOW. In the next cuts between this and when Spongebob gets sent to the Weenie place, the tattoo suddenly has the heart downside up reading WOW, or upside down reading MOM. This is never possible because MOM was supposed to be with the downside up heart, not the upside down heart.
Plot hole: In "Once Bitten", Mr. Krabs never unlocks the doors to the Krusty Krab, but at the end of the episode, Squidward enters with no problem.
Skill Crane/Good Neighbors - S4-E4
Continuity mistake: During "Good Neighbors" SpongeBob is in Squidward's house talking to him while he is in a pink nightgown. Squidward throws SpongeBob out of his house while he is in his regular brown shirt. When he is back in his house, he is in his pink nightgown again.
Enemy In-Law/Mermaidman and Barnacleboy VI: The Motion Picture - S4-E7
Continuity mistake: Patrick turned out to have put the lens cap on the camera before they started to film. But when the first scene was being filmed, there was no sign of the lens cap on the camera. There was also no sign of the lens cap on the camera when the Pearl "Boatmobile" fell off the cliff.
