Isabel is a precocious girl who is very creative and loves to draw and invent. She is also shown to love her older sister and spending time with her. Like another precocious Princess, Isabel values keeping promises no matter what to the point where she dislikes people breaking promises they made her. Also like Sofia, she loves doing her research and places a lot of faith in books she's read. Unlike her older sister, Isabel did not like Dia de los Muertos because it reminds her that her parents are dead until Elena explained why she loves it. Also unlike Elena, Isabel is not into sports. She is 11 years old as shown in "Three Jaquins and a Princess" which means she is 6 years younger than Elena.
Isabel is a tanned skin girl with a slender figure and light brown eyes, much like her sister's. Being younger, she is shorter than Elena and has long dark brown hair tied back with a bright blue ribbon.
Her signature outfit is a bright blue dress with short puffy sleeves decorated in flowery patterns. Her skirt measures up to Isabel's knees and tied around her waist is a blue bow. Isabel wears white tights and black shoes with blue bows.
For formal occasions, Isabel is seen wearing a pink-and-yellow ball gown, with a yellow ribbon in her hair.
When the evil power-hungry sorceress Shuriki invaded the Kingdom of Avalor and murdered her parents, Isabel and her grandparents were placed inside an Enchanted Painting for their protection by Alacazar while her sister, Elena, ended up trapped inside the Amulet of Avalor when she confronted Shuriki alone. Forty-one years later, Isabel and her grandparents were released from the portrait by Alacazar's grandson, Mateo, and helped Elena defeat Shuriki and liberate their kingdom.
In the series that serves as the special's sequel, Isabel is a major character alongside with the rest of her family.
In "Model Sister" it is shown that Isabel's relationship with her older sister is becoming strained due to the fact that Elena's new role as the Ruler of Avalor has given her an extremely busy schedule. She is especially angry with her sister when she discovers that Elena has been ditching her to attend King Toshi's visit when she needed her help with her invention. Elena makes it up to her by getting her invention ready in time for the Inventor's Fair.
In "A Day to Remember", Isabel does not want to celebrate Dia de los Muertos since it reminds her that she no longer has her parents to turn to. Elena manages to get her to come by reminding her of all the happy times they had with their parents and why they celebrated the Day of the Dead. Feeling better, Isabel goes to the alter and puts a drawing of her parents on the alter alongside the food tribute.
In "The Scepter of Light", Isabel is looking forward to the Eclipse Festival and finds Armando's story about Orizaba highly amusing. During the eclipse, however, Orizaba is revealed to be real. When Elena and Mateo set out to defeat her and send her back, a concerned Isabel goes after her with Gabe. When they catch up to Elena, they accidentally ruin Elena's attempt to get rid of Orizaba by blocking out the magic light Elena is bathing the moth fairy in with the Royal Coach. It casts a shadow in the path of the light which restores some of Orizaba's powers. The moth fairy tries to attack Isabel, but Elena saves her by making their father's scepter glow so bright that the light defeats Orizaba. Elena then collapses to Isabel's concern. Isabel, Gabe, and Mateo take Elena back to the castle and put her to bed where she stays for the next two days. When Elena wakes up, she reveals to a relieved Isabel that she gained magical abilities while she was imprisoned inside the amulet their mother gave her on her fifteenth birthday and that their father's scepter is also magical.
In "Navidad", Isabel is looking forward to spending Nochebuena with her friend Cristina after her father invites them to their village for the evening. However, Elena receives multiple invitations from other people who want her to attend their Navidad celebrations. Isabel supports Elena's attempts to compromise and all the while Isabel makes a Navidad Pinata. However, Doña Paloma ruins her sister's attempt by making everyone competitive to the point where everything gets ruined, including Isabel's pinata. The disaster makes Fernando decide to take Cristina home, to Isabel's sorrow. Elena fixes everything with a parranda, to Isabel's joy.
In "Olaball", Isabel meets up with King Joaquin again and becomes fast friends with his daughter Princess Caterina. She takes Cat on a tour through town. In town, they are wowed by the Voladores and Isabel tells Cat how she has always wondered how the tower works. The next day, Cat takes Isabel to the tower. Despite her misgivings about it, Isabel rides with Cat to the top where they get stuck. Gabe gets them down.
In "Three Jaquins and a Princess", Isabel shows off her latest invention, only for an accident with it to annoy Esteban, who reprimands her, hurting her feelings. As a result, as Elena consoles her, Migs arrives with his new mate, Dulce, who soon lays three eggs that will hatch into their new children. After she leaves to find Anoki Berries for their babies to eat, the eggs hatch, and Migs leaves to go help her, while Elena tells Isabel to summon her for help if she needs it when Isabel offers to watch them for Migs and Dulce. However, Isabel soon learns how difficult it is to watch the babies as they grow restless and cranky without the Anoki Berries, and she is forced to chase one of them to the kitchen, just barely hiding it from Elena when she finds Isabel in the kitchen, and Isabel is forced to lie to her big sister to convince her everything's fine. However, when one of the babies drinks Mateo's Enlarging Potion and all three ruin the Bake-Off that Elena was judging, Isabel feels guilty over not telling Elena the truth that she was struggling with watching the babies, and after Elena voices her disappointment and anger with her little sister, working with Mateo, Skylar, and Luna, they are able to round the babies up and return the one affected by Mateo's Enlarging Potion to normal before Migs and Dulce return. Once they do, they and Isabel give names to the babies, and after Esteban also makes amends with Isabel with helping her with her invention, Isabel is allowed to go play with Mingo, Zoom, and Estrella.
As Elena and the others prepare for the Jaquin Festival in "A Spy in the Palace", Isabel is with Mingo, Zoom, and Estrella as Migs, Luna, and Skylar are practicing their flyover for the ceremony. After they finish, Isabel offers to improve it by equipping them with her latest invention, Sky Painters. However, when Migs sees Skylar and Luna messing around with them, he changes his mind and quits. Isabel talks to him about how he'll let his cubs down if he doesn't perform in the flyover, convincing him to rejoin Luna and Skylar for the performance as they do their tricks before King Verago, Chief Zephyr, and other Jaquins in attendance at the festival. Isabel is unaware that Carla Delgado is with her big sister, in disguise as Armando's distant cousin "Rita Perez", preparing to steal her mother's Carnaval Tiara for Shuriki.
In "Science Unfair", Isabel is making a presentation on a volcano to her class, but none of them are interested in it until her classmates offer to help demonstrate how a volcano erupts, though Isabel was hesitant to do so. After showing it off, Isabel's teacher is so impressed that she makes Isabel the school representative in the Avalor Science Fair, where Isabel will have her entry judged by Professor Ochoa, who is Isabel's idol. As Isabel leaves with the class guinea pigs, Peaches and Paco, her teacher reminds her of how to care for them, giving her perfect idea for her project. However, after Isabel gets home and begins work on the blueprints, her classmates arrive to help. Isabel is hesitant to accept their help, wanting to do the project on her own in order to impress Professor Ochoa, so she tricks them into looking for a part she needs, allowing her to work on it her way, only for the project to go haywire during its test run, and her friends return with what they think is what Isabel was looking for, which ends up destroying the project completely. Frustrated, Isabel snaps at her friends that she lied to them and did not want their help, causing them to leave, upset at her. Elena soon arrives to confront her little sister about her actions, and reveals that when she became Crown Princess, she thought she could handle things on her own, without the need of a Grand Council, but soon learned that having friends to turn to for help and assistance was a good idea. Through song, Elena convinces Isabel to apologize and ask her friends for their help again, and though hesitant at first, her classmates agree to help once more. They finish the project together, and at the science fair, Professor Ochoa is so impressed that she names Isabel the winner, offering her a once a week class at the Science Academy with her, which Isabel accepts, only after refusing at first to accept unless her classmates could join her, which her friends assure that they don't mind if they can't join her at the Science Academy. Elena and Isabel are still unaware of Carla's deception, and now planning on reviving Fiero to aid Shuriki in her second attempt to conquer Avalor.
In "Rise of the Sorceress", Isabel is preparing to celebrate the Sunflower Festival with a dance that she had not done since the last time she performed it alongside Elena with King Raul and Queen Lucia. As she, Elena, and Luisa prepare for it, Isabel invites her classmate Christina to take part, though Christina is hesitant because of her paraplegic state, and has a hard time remembering the moves. However, seeing her father in the audience encouraging her, Christina is able to gain enough confidence to perform perfectly with Elena, Isabel, and Luisa before Elena is dragged off by Naomi after the performance, where Elena has her first face-to-face reunion with Shuriki since last seeing her after destroying her wand and freeing Avalor from her tyranny.
Later on, Isabel now knows that Shuriki is back and out for revenge, and during the events of "A Tale of Two Scepters", when Isabel is worried about Elena being at her training in Vallaestrella with Shuriki still out there, Isabel gives Elena her bracelet for good luck before Elena leaves with Skylar to begin her training with Quita Moz and the other Sun Bird Elders. Isabel later heads to her tower to practice her musical instruments, unaware she is seen by Shuriki on Cruz, being pursued by Elena and Skylar, and Shuriki soon engulfs the tower in Dark Fire to act as a distraction for Elena while she escapes back to where Fiero and the others are hiding. However, Isabel is unaware of the danger she's in as she practices, and it prevents her from hearing Elena and Gabe as they try to warn her. It is only after Elena puts the Dark Fire out with her Blaze and Gabe cheers her on for it that Isabel emerges from her tower to complain to Gabe to keep it down as she's trying to practice, before Elena dismounts from Skylar to reunite with her little sister, who's happy to see her. Later on, Elena shows Isabel what Shuriki and Fiero are up to with the Farsight spell she learned from the Sun Birds, seeing them fleeing into the jungle on Cruz and Vestia. With Isabel now fully accepting Elena's training, giving her big sister her full support, Isabel wishes Elena good luck as she leaves again on Skylar to resume her training.
Isabel soon begins her first class with Professor Ochoa at the Science Academy in "Class Act", but soon runs into trouble in the form of Javier, who believes himself to be better than the other students, and even goes so far as to insult Isabel about how she got enrolled in the Academy, much to Elena and Isabel's fury. Javier then goes even further as he sabotages the project that Isabel and her partner Tomiko were working on regarding the observatory that would be build on Mount Diablo, causing it to malfunction. Heartbroken in thinking she is not ready for the Academy, Isabel quits in shame, but Elena convinces her that she would be disappointing Ochoa if she quit, and Isabel returns to the Academy to attempt her project again, this time using some Avaloran Rubber she made earlier to make the project even better, showing up Javier, who goes back to his seat in a fuming huff, only to drop the piece he swiped from Isabel and Tomiko's original project, exposing him as the one who sabotaged their work. His excuses for why he did it fall on deaf ears with Elena, Isabel, Tomiko, and Ochoa, who furiously punishes Javier by suspending him from the project until further notice and ordering him out of the classroom now that she knew the truth. Isabel is allowed to continue her studies with Ochoa after that.
Later on, in "Song of the Sirenas", Isabel joins her grandparents, Elena, and Esteban with visiting their summer palace in Nueva Vista. However, following a parade that was held in Elena's honor, Isabel is horrified when she finds herself face-to-face with Shuriki, and all her allies in Fiero, Victor, Carla, Cruz, and Vestia. Isabel is locked in the tower with her family, and is later joined by Elena, placed in the tower by their traitorous cousin, Duke Cristóbal. Thankfully, they are busted out by Gabe, Mateo, and Naomi on Migs, Luna, and Skylar. They attempt to escape back to Avalor City on their yacht they arrived in Nueva Vista on, but are pursued by Shuriki on the Duke's yacht. Luckily, King Pescoro and his Sirenas appear to help Elena and her family out, having learned from his son, Crown Prince Marzel, that his daughter, Crown Princess Marisa, had been locked up with Elena. By the time Isabel and her grandparents and Esteban return to Nueva Vista, Elena announces that Shuriki is gone for good, having defeated her in combat moments earlier, so Isabel is relieved that her and Elena's parents can finally rest in peace at having been avenged. Isabel then watches as her traitorous cousin is sentenced to incarceration by Elena for his treason, and Elena forms a newfound friendship and alliance with King Pescoro and his Sirenas.
Isabel later returns to Avalor City to celebrate Navidad in "Snow Place Like Home", however, she soon leaves with Francisco and Luisa to deliver gifts to Christina, and is unaware of what happens while she is gone regarding the Delgados and the blizzard they summon. When she returns with her grandparents, she celebrates Navidad with the rest of her family, along with those of Naomi and Mateo as well.
Adventures in Vallestrella
Isabel stars in all five shorts with Elena and Mingo, Zoom, and Estrella as they see creatures that live in Vallestrella.
- Isabel is an inventor just like Harley Diaz, Jenna Ortega's (her voice actress) other character in Stuck in the Middle.
- As of "Three Jaquins and a Princess", Isabel is eleven years old, so she is six years younger than Elena and chronologically fifty-two years old. This makes her Disney's third oldest princess, preceded by Elena and Kida from Atlantis: The Lost Empire.