Five Personality islands are located within Riley's mind at the beginning of the film, and approximately nine at the end:
- Goofball Island - A recompilation of everything that can be considered "goofy": it has a Jack-in-the box, monkey's air horns, and a boot Ferris wheel. It also features theme park-like neon lights, just like the rest of the islands. The island was formed with a core memory of Riley running naked from her father after taking a bath, and reflects all of the times Riley ever acted goofy and funny during her childhood. It was the first island to collapse, when Riley does not laugh after her father tried to cheer her up. It is Joy's personal favorite island.
- Friendship Island - An island that represents Riley's friendships. It was created from a Core Memory Orb of the first time Riley became best friends with Meg. It collapsed when Anger made Riley angry after Meg makes a new friend. It resembles a fairground and sound stage with statues of two people conversing between each other.
- Hockey Island - First conceived when Riley was a young girl. While playing hockey with her family on the ice, she (accidentally) scored her very first goal, and a new Core Memory was formed. It led to the creation of this island. It collapsed when Riley fails at her hockey tryouts and quit. The island features structures resembling hockey sticks, helmets, pucks, a trophy, a scoreboard, and everything else relating to the sport of hockey. Snow and ice completely cover the island as well.
- Honesty Island - Represents Riley's inclination towards truth and integrity. It was first created from a Core Memory Orb after Riley became honest with her parents as a toddler about breaking a plate with a hammer. It collapsed when Riley stole her mother's credit card. It consists of neoclassical buildings, a judge's gavel and a giant pair of scales, all symbols of justice and integrity.
- Family Island - The center of all the islands and their foundation. It was created from a Core Memory of Riley baking cookies and having fun with her parents. The center of the island features a big sculpture of Riley embraced by her parents, which is surrounded by things related to Riley's family activities: a board game, Riley's house, her family tree, the family's car, and a camper used to go on vacation. It was the last island to collapse, when Riley was running away; unlike the other islands, it went down piece by piece instead of all at once. After Joy and Sadness created a brand new yellow and blue Core Memory, Family Island was expanded. It now featured the Golden Gate Bridge, indicating that Riley has accepted San Francisco as her new home.
When Riley turns twelve, several new islands are created, expanding her personality even more. These include:
- Tragic Vampire Romance Island - First conceived when Riley was 12, it represents Riley's liking for the vampire literature. It is Sadness' favorite island.
- Boy Band Island - Created when Riley was 12, it represents all of the bands that she is a fan of. Fear hopes "it is just a phase".
- Fashion Island - Disgust's favorite island, it represents all of Riley's ideas for being accepted in the society.
- Academy - Travel Island - Represents higher education.
Role in the film
All the Islands were created from the crucial memories Riley had accumulated in her childhood, and each are powered by a specific Core Memory. After Joy tries to get rid of a Core Memory created by Sadness, they are both vacuumed out of Headquarters through a tube that sends newly created memories down to Long Term Memory, accidentally bringing all of the Core Memories with them. Since the Core Memories are absent from Headquarters, the Islands are shut down, eventually breaking down and falling into the Memory Dump, causing Riley to gradually lose her personality.
When Riley's father comes up to her room and tries to make her happy, Disgust and Anger are unable to make her laugh as she declines joining her father's silliness. This causes the Goofball Island to crumble, as Joy and Sadness try to make their way out of it. The Island is destroyed and it falls into the Memory Dump, which makes Riley lose the Goofy part of her personality. Later on, during a video chat between Riley and Meg, Meg reveals that she's made a new friend back in Minnesota, making Riley feel replaced, causing Friendship to fall as well.
After Riley attempts to join the San Francisco hockey team, Hockey Island crumbles at the time, which costs Riley her skills as a formidable hockey player. With Riley becoming more and more desperate to return to Minnesota, she resorts to stealing her mother's credit card to get a bus ticket back to Minnesota, condemning Honesty Island, which then collapses the train bridge, sending the Train of Thought carrying Joy, Sadness, and Bing Bong back to Long Term Memory, instead of making it back to Headquarters.
Family Island becomes the last Personality Island to go down, and the slowest to go down. It begins to fall after Riley doesn't greet her parents and leaves to run away. As it goes down while Riley is at the bus stop, Joy uses the trampoline on the Island to catch Sadness and return to Headquarters. Once Sadness and Joy get back to Headquarters, Sadness removes the idea from the console, which causes Riley to realize what she's been doing and return home.
After Riley reunites with her parents, a new Core Memory is made containing both Joy and Sadness at the same time, recreating and establishing a larger Family Island (with the Golden Gate Bridge now part of the Island) and saving Riley's personality.
New Islands form over the year from composite Core Memories as Riley's personality develops, which include restored Hockey, Friendship, Honesty, and Goofball Islands, as well as brand new Islands like Fashion, Boy Band, and Tragic Vampire Romance.
- It is unknown if there is a limit to how many Personality Islands someone can have. While Riley has five at the beginning of the film, several more are created at the end. This suggests that as someone grows up, more of their personality develops, allowing for the creation of more Personality Islands. This is evidenced by the renovations made to Emotions' Headquarters at the end of the film, such as the larger control board.
- Honesty Island features a balance scale (symbolic of the court justice system) and a building modeled after the United States Supreme Court.
- Tragic Vampire Romance Island may have been inspired by the Twilight novels and their film adaptations.
- The globe on Academy - Travel Island is the same one featured in Toy Story.
- When the Hockey Island core memory was created, before it went down the slide, you can see a brief flash of red. This foreshadows the new Hockey Core Memory, combined with Yellow and Red.