- SpongeBob SquarePants is a main fictional character in the animated television series SpongeBob SquarePants. He is voiced by Tom Kenny and first appeared on television in the series' pilot episode "Help Wanted" on May 1, 1999. SpongeBob was created and designed by cartoonist Stephen Hillenburg shortly after the cancellation of Rocko's Modern Life in 1996. Hillenburg intended to create a series about an over-optimistic sponge that annoys other characters. Hillenburg compared the concept to Laurel and Hardy and Pee-wee Herman. As he drew the character, he decided that a "squeaky-clean square" (like a kitchen sponge) fits the concept. His name is derived from "Bob the Sponge", the host of Hillenburg's comic strip The Intertidal Zone that he originally drew in 1989 while studying at the California Institute of Arts. SpongeBob is a naïve and goofy sea sponge who works as a fry cook in the fictional underwater town of Bikini Bottom.
SpongeBob has achieved popularity with both children and adults, though he has been involved in public controversy. The character appeared in a We Are Family Foundation video promoting tolerance, which was criticized by James Dobson of Focus on the Family because of the foundation's link to homosexuality.
Patrick Star is the deuteragonist of the Nickelodeon animated comedy series SpongeBob *SquarePants, created by Stephen Hillenburg and voiced by Bill Fagerbakke. Patrick's most significant character trait is his lack of common sense, which sometimes makes him a negative influence on his best friend, SpongeBob SquarePants. Patrick is the third most recurring character on the show, appearing in 253 episodes, behind Squidward's 270 and SpongeBob's 305, although he is almost more well-known than Squidward.
- Squidward Quincy Tennis balls is a fictional character on the television cartoon series SpongeBob SquarePants. He is voiced by Rodger Bumpass. The character is an octopus, despite his name, as it was harder to draw 8 legs for development. Squidward appears in 270 episodes of the series, second only to SpongeBob's 305.
- Sandra Olivia "Sandy" Cheeks is a character in the series SpongeBob SquarePants and is voiced by Carolyn Lawrence. She is a squirrel native to Texas, and the fact of her being a land animal is often pointed out. She is friends with Patrick, Squidward, and SpongeBob.