Sandy comes from the state of Texas, and exhibits many characteristics of a stereotypical "cowgirl" character. She speaks with a heavy southern accent, and uses typical southern slang words and phrases ("This is gonna hurt worse than a jellyfish in a bucketful of electric eels."). She is very fond of her homeland and its culture, as most notably seen in the episode "Texas", in which she grows homesick for it and considers leaving Bikini Bottom to return to Texas. In that same episode, she takes great offense at SpongeBob and Patrick's negative remarks about Texas, and violently attacks them when they continue to insult it.
Sandy is one of the most intelligent and level-headed characters on the show. She is a multi-talented scientist and inventor, and originally came to Bikini Bottom to study sea creatures and their lifestyles. In "Chimps Ahoy", it is revealed that she is employed by a trio of monkeys from the surface, named Dr. Marmalade, Lord Reginald and Professor Percy. As an inventor, Sandy is capable of creating extremely advanced devices with ease. Her inventions include a manned space ship, a teleporter, a submarine that can shrink to microscopic size and go inside a person's body, and even a cloning device.
Sandy is also very athletic and physically fit. She and SpongeBob share a favorite pastime of karate, and frequently fight each other for fun. The karate they use appears to be stylized to fit that of "play karate", as they both mainly fight with chops and kicks in a cartoonish manner. There also appears to be other forms of fighting in the series, most notably in Karate Island, where three other fish demonstrate unique fighting styles, (which looks more like stylized versions of Kung Fu rather than karate).
Sandy also enjoys extreme sports and thrill-seeking, which SpongeBob also joins her in on occasion, most notably in "Prehibernation Week". Sandy possesses immense strength, and is one of the strongest creatures in Bikini Bottom. She is often seen at Mussel Beach lifting weights with Larry the Lobster, of whom she is a good friend, and other muscular fish. In "MuscleBob BuffPants", Sandy shows SpongeBob her immense biceps and intense daily exercise routine. In that same episodes, she wins the eighth annual Goo Lagoon anchor toss competition, tossing an enormous anchor 510 yards.
While generally friendly and positive, Sandy is prone to mood swings and can be vicious when angered, most notably in "Texas". In "Pre-Hibernation Week", when she believes SpongeBob has gone missing, Sandy forces everyone in Bikini Bottom to help look for him, sending them to dangerous places such as Sulphur fields and poison sea urchin coves. When SpongeBob fails to surface, she grows agitated and starts literally overturning buildings in her efforts to find him. In "Survival of the Idiots", Sandy is shown during her Hibernation as an obese, monstrous version of herself (prior to going into hibernation, animals must have tremendous amounts of body fat and energy reserves in order to survive the winter). Spongebob and Patrick enter her snow-filled Treedome and disturb her sleep, and the semi-conscious Sandy viciously attacks them, believing them to be "Dirty Dan" and "Pinhead Larry", two outlaws from her dreams.
She has also been shown to have a strong competitive streak and a high opinion of herself: in "Sandy, SpongeBob, and the Worm", she completely ignores SpongeBob's warnings about the Alaskan Bull Worm and tells him that she is "too Texas tough", only to discover the hard way that the Bull Worm is indeed too much for her to handle; in "Pressure", she continuously brags that land creatures are better than sea creatures and nearly drowns herself in an attempt to "prove" it.
Sandy first met SpongeBob SquarePants when he saw her wrestling a giant clam and ran down to save her. Since then, Sandy has been one of SpongeBob's best friends, and she enjoys various activities such as karate with him. She is also good friends with Patrick, although she is often annoyed and angered by his stupidity. Sandy is also friends with Larry the Lobster, and the two have been hinted to be romantically involved, and SpongeBob has been shown to be jealous of Larry because of this, most notably in "Ripped Pants".
The nature of Sandy's relationship with SpongeBob is somewhat ambiguous. SpongeBob has brought her flowers on several occasions, and her official biography describes her as being "the apple of SpongeBob's eye (the only thing under the sea he likes better than his job at the Krusty Krab)". In "Tea at the Treedome" amorous music plays when SpongeBob recalls Sandy's words. SpongeBob's song in "Ripped Pants" has romantic lyrics.
In the "A Random Act of SpongeBob" short, SpongeBob leaves Sandy a letter (with a bouquet of flowers) calling her the "smartest, prettiest squirrel in all of Bikini Bottom" for "Surprise Sandy Day". In the video game Battle for Bikini Bottom, after saving Squidward from Robo-Patrick, SpongeBob and Sandy commented each other on a good job while looking flushed. A book called the SpongeBob SquarePants Survival Guide, released on November 1, 2002, has a page titled How to survive a secret crush, saying that if you have a crush on someone, you have to keep it secret. SpongeBob begins to talk about him acting "perfectly natural" at the treedome, but quickly ends, saying "I've said too much!" The biggest hint was in Truth or Square, which depicted the two getting married. In SpongeBob and Friends In A Goofy Movie, SpongeBob almost reveals to Sandy his crush to her while they were trapped with Bigfoot.
Sandy joined in Spongebob's adventures in Kung fu panda, but however, she only made Camio appearences in Spongebob's adventures in Lion king and Spongebob's adventures in Lion king two, but in her true appearence of what is mention above, she appearently is Shifu's top student, and helped the shell lougers prepear for the villain leage and Tai Lung's inpending attack on the Valley of peace. she has that smart tec talking aunt personally that always know what to do. while not the leader, she'll always happly give out the winning game plan. she is like the tough as nails, but all around fun sisterly friend to the louge.
- "Oh, I'm 'Sandy' alright, I'm VERY sandy!"
- "Well, holly-wolly-ding-dang-do! Would ya' look at that!"
- "Back in Texas, we call ice cream 'frozen cow juice'."
- "Eh, I could've done that with scorpions crawlin' up my tail."
- "That's for messin' with Texas!"(Video game)
- "Who put the HIYAH- HIYAOW, 'K' in 'Karate'?"
- "Don't you dare take the name of Texas in vain!!!!"