Pearl is a whale with blonde hair styled in a ponytail, big blue eyes, and a large head in the shape of a rectangular prism. She commonly wears a pink shirt with a dark pink letter P on the front, a purple skirt, and white boots. Several episodes, most recently "Truth or Square," feature her with a light pink dress and a tiara on. When in this outfit, the hair clip that keeps her hair in a ponytail changes color from dark pink to light pink. She always has a red heart shape, remniscient of lipstick, on the front of her face.
Pearl is very intelligent and clever, but still immature. Being a sperm whale, her brain is the largest in Bikini Bottom and she is gifted in math. However, she has not grown up yet and would much rather use her math skills to count shoes than to be a bookkeeper for her father's restaurant. She wishes to be popular at school, but her peers are all shallow and rude. She has different so-called friends in every episode, and these friends are very quick to insult or abandon her. Pearl is insecure about her hobbies and is a fan of some stereotypically nerdy media, such as The Adventures of Mermaid Man & Barnacle Boy and the comic series Mecha Baleens. Despite being a teenager, Pearl sometimes enjoys activities that are more typical of little kids, such as playing with stuffed animals and having tea parties.
Mr. Krabs wants to pass his restaurant down to Pearl when she grows older, and she will also inherit his fortune later on. However, Pearl does not want to work at the Krusty Krab as a teenager at all. She wants to "live while she is young" and instead has a job at the Bikini Bottom Mall. Pearl seems to have dreams of being a star, as seen in "Culture Shock" and "As Seen on TV."
Pearl Krabs' father is Mr. Krabs. Her mother is a sperm whale, who likely married Mr. Krabs while she was pregnant with Pearl as Krabs had a banner that said 'It's a boy!', the word boy later crossed out and girl written above it when it turns out Krabs was wrong. Pearl has a dream of being a star. She did a "cheer" for the Krusty Krab at Squidward's talent show. Pearl is used as a back-up invisible boatmobile for the semi-retired underwater superheroes Mermaid Man and Barnacle Boy, in a movie SpongeBob and Patrick were creating.
Her favorite band is an all-boys band called "Boys Who Cry." She also enjoys shopping at the mall. She can also play the tuba. At school, she is a member of the "Most Frequently Pictured in the Yearbook" committee.
Pearl's immediate family consists of her father Mr. Krabs, her mother Mrs. Krabs (who is no longer with them), her grandmother Betsy Krabs, and her grandfather, Victor Krabs. With the exception of her mother, all of Pearl's family members are crabs.
Pearl and her father's different species have never been directly explained in an actual episode, but it has been confirmed by many pieces of merchandise and the series' crew members that Mr. Krabs was married to a whale who gave birth to Pearl. SpongeBob's Trivia Book states that Pearl "takes after her mother." According to creative director Vincent Waller, Stephen Hillenburg has received many letters requesting an origin story for Pearl, but he is strongly opposed to "solving the mystery" of how she became a member of the Krabs family. An episode focusing on her origin was written and started early development stages, but this episode was shelved due to Hillenburg's disapproval.
Pearl was named after the phrase "mother-of-pearl," which Mr. Krabs says whenever he is scared. He does this as a reference to the absence of Pearl's mother. Since he only uses the phrase when he is scared or shocked, it is reasonable to believe something tragic happened to Mrs. Krabs.
At Dragon Con in 2016, Lori Alan and Rodger Bumpass performed a skit about Pearl's origins, playing their characters Pearl and Squidward. The skit confirms that Pearl is not adopted, that her mother was a whale, and that Mrs. Krabs' location is secret. Bumpass joked that Mrs. Krabs was taken to Sea World.