SpongeBob Squarepants is a square, yellow sponge who lives in a pineapple house. He wears knickers and a gap-toothed grin. He has an unending bounty of innocence and old-fashioned ethics and has earned his dream job as an underpaid fry cook at the Krusty Krab. SpongeBob has a pet snail named Gary who writes poetry and inexplicably meows like a kitten. SpongeBob's personal motto: "Go SpongeBob, Go SpongeBob, go self!"

Patrick Starfish is a simple-minded pink surfer dude who is SpongeBob's best buddy. He lives under a rock. SpongeBob's best friend and neighbor. Jobless and not known for his smarts.

Mr. Krab owns the Krusty Krab, where the culinary specialty is the Krabby Patty. Mr. Krab can usually be found counting his money and is in a major fast food rivalry with Plankton, owner of the Chum Bucket. Eugene H. Krabs: Mr. cheap. Owner of the Krusty Krab. Employs SpongeBob and Squidward.

Sandy Cheeks is a squirrel from Texas. She's the only rodent in the underwater world and is a good friend of SpongeBob's and Patrick's. She wears a bikini top and a diver's air-bubble helmet because everyone knows squirrels can't breathe under water. When SpongeBob meets Sandy in the first episode, she greets him with, "Hold on there, little square dude." Sandy Cheeks: Needs a diving suit because she's a land (surfer) squirrel. Loves extreme sports and karate.

Squidward Tentacles is SpongeBob's grouchy neighbor and also an employee at the Krusty Krab. He plays the clarinet and subscribes to Martha Stewart Living. Squidward Tentacles: Gets the boring award. Loves playing the clarinet. Thinks SpongeBob and Patrick are annoying.