Krabby Land / The Camping Episode - S3-E19
Other mistake: In "Krabby Land", Mr. Krabs as "Krabby The Clown" finishes his short speech and goes into his office. When he slams the door, bubbles float up and those bubbles stay motionless in the air for a few frames.
Krabby Land / The Camping Episode - S3-E19
Continuity mistake: In "The Camping Episode", Squidward sets down a blanket to lay under the stars and in a couple of shots, the blanket disappears.
Krabby Land / The Camping Episode - S3-E19
Continuity mistake: In "Krabby Land", Spongebob goes to check his motivational quote and from far away, the page is flipped up. But in the next shot, it is a close up and the page is flat against the stack. In the following shot, the page is flipped up again.
Krabby Land / The Camping Episode - S3-E19
Continuity mistake: In "Krabby Land", Mr. Krabs is in his boat with Spongebob in front of the playground filled with children. After looking through a pair of binoculars, he drops them in front of the boat. However, in the next shot the binoculars are gone.

SpongeBob Meets the Strangler / Pranks a Lot - S3-E20
Other mistake: Pranks a Lot: When everyone is cheering on Spongebob and Patrick at the end, Sandy whistles by putting her hand through her helmet. Impossible. (00:23:30)
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.
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.

SpongeBob Meets the Strangler / Pranks a Lot - S3-E20
Continuity mistake: 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.
SpongeBob Meets the Strangler / Pranks a Lot - S3-E20
Continuity mistake: 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.
SpongeBob Meets the Strangler / Pranks a Lot - S3-E20
Revealing mistake: 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.
Suggested correction: The clothes are being held up by a coat hanger. It may be hard to see due to it blending in with the wall color, but if you look closely, it's there.
SpongeBob Meets the Strangler / Pranks a Lot - S3-E20
Continuity mistake: In Spongebob Meets The Strangler, the Tattletale Strangler's dots on his head change numbers constantly. Sometimes there are 5 on his right, sometimes 6, sometimes his left side has a scar and 5 dots, sometimes a scar and no dots.
SpongeBob Meets the Strangler / Pranks a Lot - S3-E20
Plot hole: In the end of "Pranks A Lot" SpongeBob and Patrick glue the door shut in order to keep Mr. Krabs inside the Krusty Krab. When SpongeBob And Patrick are visible again, it turns out that a lot of customers have entered the Krusty Krab to see SpongeBob and Patrick naked. All of those people had no way to get into the Krusty Krab with the doors glued shut. It can't be that they broke down the doors, as they're still there.
Suggested correction: Mr. Krabs most likely washed the glue off the doors and let the people in.
Fear of a Krabby Patty/Shell of a Man - S4-E1
Continuity mistake: In the episode 'Shell of a Man", when SpongeBob pushes over Mr. Krabs' shell off of the chair at Mr. Krabs' desk, you can see that there are 2 eye holes, a nose hole, and a very large hole for the mouth. But when SpongeBob puts the shell on, both his nose and mouth are in the large mouth hole, and his eyes are in the eye holes. But there is no nose hole.
Fear of a Krabby Patty/Shell of a Man - S4-E1
Continuity mistake: When Mr. Krabs drags SpongeBob back into the kitchen, Squidward's facial expression changes between shots.
The Lost Mattress/Krabs vs. Plankton - S4-E2
Continuity mistake: Krabs vs. Plankton: When Krabs meets with the attorney, Bottomfeeder, both the exterior and interior door knobs on his office door appear and disappear in various shots, even consecutive shots.

Have You Seen This Snail? - S4-E3
Revealing mistake: After SpongeBob tells Patrick, "I can't find Gary," text that reads "Rough Draft Korea" briefly appears on screen during the bubble transition. (00:08:24)
Have You Seen This Snail? - S4-E3
Other mistake: When Gary comes back at the end, when Gary meows and Spongebob says, "Yeah, like that," the tears in his eyes disappear for about half a second. (00:22:50)
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.
Have You Seen This Snail? - S4-E3
Continuity mistake: Have You Seen This Snail: After the customer asks for a refund it cuts to SpongeBob crying in the kitchen, and when Krabs walks in the door opens at the left side with no knob, but when Krabs tells SpongeBob that a problem can be solved with a little hard work, that door now opens at the right side with a door knob.