Lagoona Blue is a 2010-introduced and all-around character. She is a special kind of sea monster , as she is the daughter of a sea monster and an ocean nymph, which allows her more places to travel to than either of her parents. She is a student at Monster High, having transferred from the Great Scarrier Reef, and if there is one person in the entire school who could befriend anyone, it's Lagoona. She is patient and considerate, but does not sugarcoat her message or allows anyone to walk over her. Which, along with her considerable skill, is why she's been chosen as the captain of the Swim Team. The one exception to her no-nonsense attitude is her boyfriend, Gillington "Gil" Webber. She gives him leeway beyond her standards despite the harm it does her because she is aware that his home situation is far from ideal. She is not happy with the situation, but she knows she would also not be happy without him.
She is voiced in English by Laura Bailey.
In the anime adaptation she is voiced by Aina Kusuda
Lagoona has a very friendly and laid-back personality, even her clothes reflect her easygoing nature. Most of the time, Lagoona is very calm and level-headed, but she is prone to strong emotions, especially when it comes to romance and friendship. She is almost never outright mean, but she is passionate about friendship, and will defend her friends fiercely. However, she is forgiving and won't stay mad for long, as it's just not her nature. Due to her kind and friendly nature, she seems to have a lot of friends.
Lagoona is also an environmentalist; trash and pollution in the ocean anger her, and she shows sympathy to many aquatic elements, including fish, frogs and all water creatures. She loves helping water creatures and wishes for the ocean to be clean.
Lagoona has pale blue scales that cover her entire body, as well as webbed hands and fins potruding from her lower arms and legs. She has curly blonde hair that's streaked blue due to the chlorine in the school's pool, as well as freckles that dot her face.
In the film, a scientific expedition takes a steamship journey up the Amazon River, in search of fossilized remains that they believe provide the link between man and fish. Meanwhile, members of the research team are systematically killed by a mysterious being, eventually revealed to be the prehistoric fish creature whose skeleton they were searching for. The Gill-man was played by Ben Chapman (on land) and Ricou Browning (in the water); Dr. David Reed was played by Richard Carlson, and Kay, the lead scientist's girlfriend, was played by Julie Adams.
Lagoona's father "doesn't really live on land. For sure, he's got a little beach house where Lagoona Blue lives. It's got a killer dock that goes out over the water." According to her School's Out diary, her mother is an ocean nymph who "still lives in the same scary sweet little grotto as she did when dad met and married her. Being a nymph means that mom can leave the water and hang out on land as long as she doesn’t travel too far from her grotto otherwise she gets really weak".
In the Monster High book series, Lagoona's parents live in Australia, but she lives with her uncle (unnamed) and her aunt Coral in Salem. Lagoona moved in Salem as a foreign exchange student from "down under".
In "Parent-Creature Conference" the ghouls tell Slo Mo that he is supposed to be posing as Lagoona's Great-Aunt Lantic; this relative may or may not really exist. In her 'Basic' diary, Lagoona mentions having a few cousins 'living up north'.
Lagoona is very easygoing, and wants everyone to be friends; as such, she is friends with everyone, even the hard-to-get-along-with Cleo (but she hangs out with Cleo, Ghoulia, Frankie, Clawdeen, Abbey and Draculaura the most, so they're probably her closest friends). She is rarely seen disagreeing with anyone, except Toralei when she openly mocked the fearleading team and her. In "Bean Scare, Done That" she stated that she, Frankie, Cleo, Draculaura, Gil and Clawdeen have 500+ friends all together.
Lagoona's pet is a piranha named Neptuna who is carried around in a fishbowl purse. She is shown to be very feisty, and enjoys nipping other monsters when they least expect it. She has not appeared in the cartoon although other piranhas are seen in "Fright On!" and presumably owned by Lagoona and/or other swim team students. In Lagoona's diary it states that she brings her to classes secretly in her fish bowl purse.
Gil and Lagoona started seeing each other soon after they met in "Blue Lagoona" and "Hatch Me If You Can". It is shown in the beginning of the show that Lagoona tended to draw her and Gil together and also stare at him dreamily.
Gil's family holds a negative view on salt water monsters, which Gil kept a secret from Lagoona until "Road to Monster Mashionals". Lagoona encouraged him to take a stand against his parents; he tells her he informed his parents, but in "HooDoo You Like?", Toralei Stripe arranges for an entire page in the Fearbook to be dedicated to Gil's and Lagoona's relationship, forcing Gil to reveal that he lied, and his parents didn't know they were dating.
Lagoona gave him an ultimatum: either he'd stand up for them, or he should forget about her. After a lot of doubt and self-reflection, Gil chose the honorable path in "Desperate Hours" and told his parents he was dating a creature from the sea that was nothing like the horrible creatures they always talked about. His parents didn't take kindly to it, but the strain went off his and Lagoona's relationship.
After the summer vacation, Gil didn't return to Monster High because his parents enrolled him in a different school to keep him away from Lagoona. He returned in "Here Comes Treble", and he explained in "Fright On!" that his parents gave up and allowed him to go back to Monster High and his salt water love.
- October 8, 2008: Mattel requests the trademark for Lagoona Blue.
- May 5, 2010: The Monster High website goes live, featuring Lagoona Blue's profile.
- May 5, 2010: Lagoona Blue's profile art is revealed.
- May 5, 2010: Lagoona Blue makes her animated debut in the Higher Deaducation commercial.
- May 5, 2010: Lagoona Blue makes her 2D cartoon debut in "Jaundice Brothers".
- Early July, 2010: Lagoona Blue's first doll is released as part of the 'Basic' series.
- Early July, 2010: Lagoona Blue makes her diary debut in her 'Basic' diary.
- September 1, 2010: Lagoona Blue makes her Monster High book debut in Monster High.
- Early December, 2010: Lagoona Blue's Friends plushie is released.
- February 12, 2012: Lagoona Blue makes her 3D cartoon debut in "Why Do Ghouls Fall in Love?".
- October 22, 2014: Lagoona Blue makes her anime debut in "Monster High Life Is Amazing!".
- Lagoona seems to be able to talk to frogs and other amphibians, like Cleo can talk to snakes, and Draculaura with bats.