Valentine's Day / The Paper - S1-E16
Continuity mistake: In "Valentine's Day", Patrick starts searching his present in the fair. Then he goes to a mountain and falls thinking that there will be his present. This mountain wasn't there before, even when they arrived to the fair.
Jellyfish Hunters / The Fry Cook Games - S2-E16
Continuity mistake: When Patrick rips up some grass, between shots the grass appears again.
Welcome to the Chum Bucket / Frankendoodle - S3-E2
Continuity mistake: Frankendoodle erases the door in SpongeBob's house (when they're fighting in the night). A few moments later you see the door is back.
Your Shoe's Untied / Squid's Day Off - S2-E2
Continuity mistake: In "Squid's Day Off" Squidward gets mad at Spongebob for ringing a bell over and over again. It shows the bell in the window to the left. Later, when it shows Squidward throwing the cash register onto the ordering desk, the bell is gone from the window. In the next shot of Spongebob, the bell is back in the window. Then, when Squidward shouts "No." the bell is gone again.
Something Smells / Bossy Boots - S2-E1
Continuity mistake: In Something Smells, when Patrick tells the story about the ugly barnacle to help cheer Spongebob up, the chair that Spongebob sits in disappears in the next few shots.
Mermaid Man and Barnacle Boy III / Squirrel Jokes - S2-E4
Continuity mistake: In Squirrel Jokes, when Spongebob gives Sandy the flowers, the number of the flowers varies from 6 to 8 in different shots.
Naughty Nautical Neighbors / Boating School - S1-E4
Continuity mistake: When Patrick runs out of Spongebob's house after Spongebob cries and says he's cheating, the lower right window beside the door is gone.
The Bully / Just One Bite - S2-E17
Continuity mistake: In one bit, Spongebob handcuffs himself to Squidward. When Squidward takes the Krabby Patty, the handcuffs are gone.
Atlantis SquarePantis - S5-E12
Continuity mistake: When SpongeBob and Patrick are in the cave, the points on the amulet change size and shape between shots.
Chocolate With Nuts / Mermaid Man And Barnacle Boy V - S3-E11
Continuity mistake: When SpongeBob and Patrick are pretending that they need an operation and that fish falls down the stairs, if you look at Patrick's head he has no bandage on his head. But when he looks at SpongeBob right after that fish falls down the stairs, a bandage suddenly appears on his head.
Mermaid Man and Barnacle Boy IV / Doing Time - S3-E1
Continuity mistake: When mermaid man and barnacle boy are looking for the invisible boatmobile, there are boats all over, even in front of the windows, but when Spongebob is inside running towards the door there are now no boats visible out the window.
Continuity mistake: When Patchy lifts his eye patch to rub his eye and puts the patch on his right eye. In the next shot the patch is on his left eye.
Naughty Nautical Neighbors / Boating School - S1-E4
Continuity mistake: When Squidward starts making pink bubbles with messages, he goes to his backyard. Notice he never closed the back window of his house. When he starts laughing because of the messages, suddenly the window is closed. After Patrick saves Squidward, the window is still closed, but when they go to the front of his house, the window is open.
Mermaid Man and Barnacle Boy III / Squirrel Jokes - S2-E4
Continuity mistake: During Spongebob's act, he says to the audience, ".I'd like to give a special thanks to my friend Sandy over here" and the spotlight moves from Spongebob to Sandy. A few shots later, when Spongebob is talking to Sandy, the spotlight is suddenly no longer on Sandy. Then when Spongebob yells "Am I right?" to the audience, the spotlight is on him and as he turns to talk to Sandy again, the spotlight is altogether gone; it's not on either one of them.
Krab Borg / Rock-a-Bye Bivalve - S3-E8
Continuity mistake: In the scene where SpongeBob has given his pants to the clam, two continuity errors appear. First, Patrick puts his head in the pants and he says that the clam is hungry. A lot of holes are in his head. In the very next shot, the holes are gone. This is really obvious. The other continuity error is that before Patrick gets those holes, SpongeBob isn't with his pants. When he tries to give the Patty to the clam, he's suddenly with his pants, when the little clam is supposed to have his pants.
No Free Rides / I'm Your Biggest Fanatic - S2-E10
Continuity mistake: In "No Free Rides", when Spongebob and Mrs. Puff are fighting in the car, they eventually go over a cliff. We see a view of a police car under them, next to the cliff and a billboard. We also see a shot of the police car facing a hill or two. The car flies out of nowhere onto the police car, from behind a hill, not off the cliff. The landscape in the scene changes in each shot.
Pressure / The Smoking Peanut - S2-E12
Continuity mistake: In The Smoking Peanut, after Spongebob sees Sandy he runs home. When he's trying to open the door if you look to the right the ground is completely flat and has nothing in it. Yet when Patrick comes, while he is saying, "I followed these footprints to this exact spot", there are footprints.
The Sponge Who Could Fly (aka The Lost Episode) - S3-E16
Continuity mistake: When the tape pours out of the VCR at the end of the show, Patchy the Pirate gets tangled in it. A shot later, the tape is three times longer than it was the shot before it.
Jellyfishing / Plankton! - S1-E3
Continuity mistake: In "Plankton", when Plankton is controlling Spongebob, Spongebob goes to put his pants on, but Plankton has him walk through them. As they're walking towards the pants, the tie is red. As they're walking through the pants, the tie turns black. As they walk away from the pants, the tie is red again.
No Free Rides / I'm Your Biggest Fanatic - S2-E10
Continuity mistake: When Spongebob writes an essay, at first he's in the middle seat on the front row, but after he gets his pen, he sits down at the desk to the very right.
Suggested correction: No, he is sitting in the middle the whole time.