SpongeBob SquarePants is a sea sponge who lives in a pineapple under the sea, while his squid neighbor, Squidward Tentacles, lives in a moai. SpongeBob's other neighbor and best friend is a pink starfish named Patrick Star, who lives under a rock. SpongeBob and Patrick live on either side of Squidward Tentacles, much to Squidward's dismay.
SpongeBob's house-pet is a snail named Gary, who meows like a cat. Although Gary only speaks in a few episodes, the characters have shown an ability to understand him. In addition to this, underwater worms bark exactly like dogs, and are kept on chains. Jellyfish are the equivalent of bees; buzzing, "stinging" with poison, and producing delicious "jelly", mocking the name "jellyfish", while still referring to a bee's honey. Clams act as birds, and fish act as the citizens of the community but generally are not important characters.
Although the denizens of Bikini Bottom live underwater, they mostly do not float, and gravity usually applies. A flurry of bubbles accompanies actions in many of the episodes to remind the viewer that the setting is underwater. However, the laws of physics in Bikini Bottom change somewhat from time to time, but mostly the water acts like air. For instance, characters can pour a glass of liquid, just as we do above the sea. Bikini Bottom has functional baths, pools, and toilets, and there are lakes and streams. In Battle for Bikini Bottom and a regular beach setting, Goo Lagoon, underwater liquid is referred to as goo. Once, during an episode set in a wilderness area, Patrick questions how a camp fire is possible on the lagoon bottom. As soon as the question is asked, the fire is immediately extinguished with a sizzle; however, this is only used for comedic effect, as fire is often used and seen.
SpongeBob works as a fry cook at the Krusty Krab, a fast-food restaurant, with Squidward as the cashier. The Krusty Krab is owned by Mr. Krabs, a greedy, penny-pinching crab and ex-Navy officer. Sheldon Plankton is Mr. Krabs's arch enemy who owns a low-rank fast-food restaurant called the Chum Bucket across the street from the Krusty Krab. The Chum Bucket has almost never had a customer, and Plankton spends most of his time plotting to steal the recipe for Mr. Krabs's popular Krabby Patty burgers. Only in the movie does he succeed; the formula is never actually revealed to the audience. This fact is mocked in the Krusty Krab Training Video episode, where the episode cuts off before the video reveals the recipe. Plankton's computer wife, Karen, alternately helps him in his schemes or bickers with him.
Sandy Cheeks is another friend of SpongeBob. She is a squirrel that lives in an underwater dome in Bikini Bottom. She was sent there to do research for her chimpanzee bosses. Sandy is from Texas, and speaks with a Texan accent. Sandy is an expert at karate. When not inside her tree-dome, she wears an astronaut-like suit because she cannot breathe in water. Sandy hibernates once a year.
Instead of cars, the residents of Bikini Bottom drive boats, known as "boatmobiles". SpongeBob is still in boating school after failing the driving test over seventy-two times.
SpongeBob and his friends live in the underwater city of Bikini Bottom. Bikini Bottom is like a regular city with a downtown, suburbs, coastal areas, its own airport, bus system, and fair park. Stephen Hillenburg said once that Bikini Bottom was loosely based on Seattle, Washington. An example of this statement is in the episode "Pre-Hibernation Week". Sandy and SpongeBob were fighting on a tall structure called the Sea Needle, referring to the Space Needle, a tall structure in Seattle. Hillenburg has said that he wants to leave the location of Bikini Bottom to the imagination, claiming that the Baywatch scene from the movie was just a reference to his favorite show of all time.
Bikini Bottom is a city that is the main setting of the series, located at the bottom of the Pacific Ocean,It is where the series' main characters live and where most of the episodes take place. The city consists of various businesses, including restaurants, stores, and manufacturers. The city has a stable economy, balanced education and health systems, a structured government, and a firm law enforcement system. There are even stadiums, amusement parks, and other recreational facilities.
Bikini Bottom's geography is shown as consisting of mountains, dense forests, lakes, lagoons, caves, grasslands, reefs, rivers, and barren desert wastelands.
The city is divided by its main road, Conch Street, which runs from downtown and past the homes of SpongeBob, Squidward, and Patrick, through the Krusty Krab, the Chum Bucket and the Reef Theatre cinema. The road intersects with Barnacle Road and Coral Avenue. Anchor Way is not far off from Conch Street. Conch Street runs north-south as revealed in the SpongeBob SquarePants: Battle for Bikini Bottom video game. Downtown Bikini Bottom is located in the northernmost point of the city, while SpongeBob, Squidward, and Patrick's House are on the southern part of the road. Goo Lagoon is located west of the road, while Jellyfish Fields is to the east. Other establishments are located more southerly, including Sandy's house, Shady Shoals retirement home, the Krusty Krab, the Chum Bucket, and the Movie Theater. The Kelp Forest is located more southerly.
In the center of Bikini Bottom, the citizens work and live in large, gray buildings made of metal. There are some other forms of buildings, mostly aquatic-themed as seen above. Further out from the town citizens need to use whatever is available and easy to live in, such as Patrick's rock, SpongeBob hollowed-out pineapple, and the Easter Island Head Squidward lives in.
Surrounding towns include Rock Bottom, New Kelp City, and Ukulele Bottom.