Simón Álvarez is a main character on Soy Luna. He is a funny and caring boy from Mexico, who loves music and skating. Simón is Luna Valente's best friend, but his feelings for her go beyond just friendship.
Simón is sweet and cares about his best friend, Luna, a lot. He is full of jokes and very humble. He has a good heart and is always ready to give words of encouragement and cheer on his friends. His passions are skating, writing songs and playing the guitar.
Simón is out of school and works at Foodger Wheels in Cancún, Mexico. He is not the best worker, often neglecting his duties to play the guitar and goof off. He enjoys skating, but it is more of a hobby than a passion, in contrast to his best friend Luna Valente. One day at work, Luna tells Simón about a dream she had that included a melody. Simón takes the melody and writes a song around it with his guitar. Simón is saddened when he learns that Luna is moving away to Argentina, and must say a heartfelt goodbye to her. While Luna is in Argentina, Simón calls her daily and sends her recordings of the song he's working on, which is now called "Valiente" (Brave). After losing his job at Foodger, he decides to move to Buenos Aires with his last paycheck.
In Argentina, Simón finds Luna at Jam & Roller hours before the first Open Music of the year. Luna introduces him to Pedro and Nico, who are looking for a guitarist. Simón offers them "Valiente" to play, and the performance goes well. Together, they decide to form the Roller Band. The Roller Band performs at every subsequent Open Music, and writes two additional songs "Un destino" and "Invisibles." They film a music video for "Invisibles," which premieres at the Boys vs. Girls Open Music. Simón ends up spending most of his time with Pedro and Nico because he got a job at Jam & Roller and moved into their apartment after having to hide in the Benson Mansion's warehouse during his first weeks in Argentina.
Since Simón really wanted to focus on his music and the Roller Band, he initially declines Luna's partnership in the International Skating Competition. After seeing just how much Luna wants to be in it, though, he changes his mind and pairs up with her. During rehearsals for the competition, Simón tells Luna that he likes her and tries to kiss her, but Luna only likes him as a friend. Simón's feelings for Luna do not change, though, and he writes "Eres," a love song, for her. Simón and Luna make it to finals of the skating competition and travel to Puerto Madero together. There, he meets Mar and goes on a date with her. Luna sees Mar kiss Simón's check and gets jealous. To reassure Luna of his feelings, Simón shows "Eres" to Luna.
Hours before Simón is meant to compete in finals, he is kidnapped by Tino and Cato due to a misunderstanding. He is eventually let go, but he is too late and misses his performance time with Luna. Simón arrives just in time to see Matteo Balsano kiss Luna, devastating him.
Beyond Luna and the Roller Band, Simón made some other minor relationships at Jam & Roller. Through Luna, Simón befriended Nina Simonetti, who was the first person he told about his crush on Luna. When Jazmín Carvajal met Simón, she developed a crush on him but was discouraged by Ámbar Smith from pursuing it. Ámbar's advice was futile, as Jazmín asked Simón for music lessons to be closer to him. Additionally, Matteo immediately took a disliking to Simón, which Simón reciprocated. Although, since both of them were keeping their feelings towards Luna a secret, it was somewhat unclear to them exactly why they weren't getting along. Their rivalry came to a head at the Chicas vs. Chicos Open Music when they almost begin to fight on stage before they were separated by Luna.