Jellyfishing / Plankton! - S1-E3
Continuity mistake: In Plankton! When Plankton pulls out a radio player to play his evil music on SpongeBobs pillow, it has disappeared when Spongebob wakes up. SpongeBob didn't move on it.
The Secret Box / Band Geeks - S2-E14
Audio problem: At the end of "Band Geeks" when everyone is playing "Sweet Victory" at one point Mrs. Puff is shown playing the guitar. When this happens, you can see the others in the background not doing anything, even though their instruments are heard.
Procrastination / I'm With Stupid - S2-E19
Continuity mistake: In "Procrastination" when Spongebob is moving back and forth on his chair while writing his essay there is no pencil on the desk, but when he goes back to work on the essay there is.
Suggested correction: The pencil is sitting to the right of the paper the entire time. It's hard to notice at first, but it's there.
Best Day Ever/The Gift of Gum - S4-E20
Revealing mistake: When Squidward says "I suppose if you haven't fixed my clarinet, the concert would have been a bust", Sandy's tail is the same color as her suit.
SpongeBob Meets the Strangler / Pranks a Lot - S3-E20
Plot hole: 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.
SpongeBob Meets the Strangler / Pranks a Lot - S3-E20
Plot hole: 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.
Revealing mistake: In "Not Normal" when SpongeBob says "Hmm. This video tape should help," his left arm is missing. (00:01:25)
You Wish ('Shanghaied') / Gary Takes A Bath - S2-E11
Audio problem: In the beginning of "Shanghaied" during the Patchy the Pirate segment, Patchy says, "Roll the cartoon" but his mouth obviously says something else.
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.
Suggested correction: Maybe Squidward has a key to the Krusty Krab that Mr. Krabs doesn't know about.
He could still have a key, but we don't see it.
Whether or not Squidward owns a key to the Krusty Krab is beyond the point of the mistake here. The point is that Squidward is able to walk into the Krusty Krab despite the doors being locked, and he doesn't use a key or anything else to unlock them. He just pushes them open.
Maybe the doors were not locked properly.
Revealing mistake: At the end of "Wormy", Patrick's eyes are missing.
Club SpongeBob / My Pretty Seahorse - S3-E12
Revealing mistake: In Club SpongeBob, when SpongeBob, Patrick and Squidward are in the forest, Squidward asks the magic conch shell if he can have something to eat. Straight after he asks "Can't you say anything else but 'No'?", it has a close-up of the shell. But Squidward's arm appears to be yellow, like SpongeBob's. This error was later corrected in 2019 when the episode was remastered for digital releases.
Tenacle-vision/I Heart Dancing - S7-E8
Character mistake: In "I Heart Dancing", the lady at the Krusty Krab tells Spongebob the dancing audition is the next day. Later, Spongebob is practicing at Squidward's house for a whole night, and the next morning Squidward says they have one more day to practice, even though the audition should have been that day.
Suggested correction: The audition could have been during the afternoon.
Mermaid Man and Barnacle Boy IV / Doing Time - S3-E1
Plot hole: In "Mermaid man and Barnacle Boy", Plankton is shown as taller than the town at the end of the episode. However, when Spongebob is shrinking the people of Bikini Bottom, their sizes in the pickle jar seem to be equal with Plankton's actual height. In reality, Plankton should have been around the same size as the rest of Bikini Bottom's residence after the shrinking, not 5 times taller.
SpongeBob Meets the Strangler / Pranks a Lot - S3-E20
Continuity mistake: 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.
Jellyfish Hunters / The Fry Cook Games - S2-E16
Plot hole: As Spongebob is trying to let the Jellyfish out of their enclosure after discovering what Mr Krabs is doing to them, Krabs says, "That door will only open if I say...open." Then he suddenly realises what he's said and the door opens. How come the door didn't open when in his sentence he first said open? The door didn't activate itself until he said open the second time.
Suggested correction: Two likely explanations: 1. He said it more the 2nd time. 2. There was a delay.
Continuity mistake: When all of Spongebob's friends are formed around him, there's one scene where Pearl's hat disappears and then reappears, so for a few seconds she's completely bald. Her hair isn't even there.
The Secret Box / Band Geeks - S2-E14
Continuity mistake: When SpongeBob is sneaking to Patrick's house, Squidwards house is missing.
Something Smells / Bossy Boots - S2-E1
Continuity mistake: In "Something Smells," when SpongeBob is playing the organ at night, he turns around and his glasses are on. In 2 of the 3 shots, the glasses disappear.
Have You Seen This Snail? - S4-E3
Continuity mistake: 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.
Jellyfishing / Plankton! - S1-E3
Continuity mistake: In Jellyfishing, when Patrick puts the net in Squidward's hand, at first it is in his left hand, but when he gets the jellyfish on the king jellyfish, it is on his right hand.
