The Kelp Forest first appeared in "Club SpongeBob," as the main setting of the episode. SpongeBob, Patrick, and Squidward land in the Kelp Forest after Squidward tries to leave SpongeBob's clubhouse and accidentally causes the tree that it was on to bend and fling the clubhouse into the forest. Squidward attempts to escape and when he gives up, he tries to survive. SpongeBob and Patrick follow the advice of a toy called "The Magic Conch Shell." They do nothing until a conveniently timed airplane crash causes them to gain food because the pilot dropped the load, which was picnic supplies. Squidward attempts to eat the food, but the Magic Conch Shell won't allow him to. Eventually, a Forest Ranger arrives to save them, but he also follows the advice of the Magic Conch Shell, which leads the four to do nothing.
The Kelp Forest then appears again in "Bummer Vacation" when Mr. Krabs tries to get rid of SpongeBob. When Mr. Krabs has enough of SpongeBob's schemes to get back in the Krusty Krab, he tells SpongeBob that he will take him home. However, they drive past SpongeBob's house and end up in the Kelp Forest. Using SpongeBob's spatula, Mr. Krabs tells SpongeBob to go fetch it and SpongeBob does, but before he can get back, Mr. Krabs is gone.
The Kelp Forest returns in "To Save a Squirrel," as the main setting of the episode once again. SpongeBob and Patrick try to survive after falling out of Sandy's Truck. In the end, Sandy reveals that it was a test to see if they were strong enough to survive.
The Kelp Forest returns 4 seasons later in "Eek, an Urchin!" After a run in with some Sea Urchins, SpongeBob is tasked to get rid of them. He goes farther away from the Krusty Krab. He eventually comes to the Kelp Forest and calls Mr. Krabs, who tells him to go farther.
It has also appeared in numerous video games.
Its first video game appearance was in Battle for Bikini Bottom where SpongeBob has to save some campers. In the PC version of the game, the robots kidnapped Gary and kept him in the forest.
The Kelp Forest then appears in The Yellow Avenger, where he has to hide something for Patrick, get some kelp for Gary's snail food, and deliver some pickles to customers who got Krabby Patties that don't have pickles on them.
Although this is not known for sure, the history of the Kelp Forest may have began in the prehistoric times.
In "SB-129," there is a small area in which the Primitive Sponge either ate or lived. This area might be where the Kelp Forest began.
Kelp Swamp is a large swamp in the middle of the Kelp Forest. It consists of various islands alongside the swampy waters.
Kelp Caves is a large cavern in the middle of the Kelp Forest. To get there one must go across the bridge that is located in the Kelp Swamp. It is slightly maze-like in design.
Kelp Vines is an area outside of the Kelp Caves, consisting of a large vine slide. Mermaid Man is the world record owner of the slide for reasons unknown.
Club SpongeBob Camping Area is a clearing in the middle of the forest, which was briefly inhabited by SpongeBob, Patrick, and Squidward after they were hurled here by SpongeBob's Kelp Tree.
Kelp Forest Road is a road that runs through the Kelp Forest. This was only seen in "Bummer Vacation," when Mr. Krabs drove SpongeBob far away from the Krusty Krab in order to keep him from coming back until after his vacation time is up. It is most likely the road is used for hikers.
In the video game Bikini Bottom 500, one of the race tracks themes is Kelp Forest.
The Kelp Forest is displayed on the boot-up/installation window for the Employee of the Month game, although it is not a location in the game. There is also a restaurant located on top of a quaint hill that's rising out of the kelp forest called "Sublime Seafoods."
Due to the thickness of the kelp and the size of the forest, it is very easy to get lost there.