Early career Making her debut in 2014, Velasquez won her amateur debut via second-round submission, later that year, kicking off her professional career with a decision victory in a
Rio de Janeiro regional promotion. She won her next 4 fights, collecting a 5–0 record, in the process also winning the 1RC Vacant Bantamweight Championship and defending it once. She was eventually offered a multi fight contract with
Bellator MMA. Juliana faced Rebecca Ruth at
Bellator 197 on April 13, 2018. She won the fight via front kick to the body in the third round. In her third fight for the promotion, Velasquez faced
Alejandra Lara at
Bellator 212 on December 14, 2018. She won the fight via split decision. Juliana faced Kristina Williams at
Bellator 224 on July 12, 2019. She won the fight via TKO in the second round. Juliana faced Bruna Ellen at
Bellator 236 on December 21, 2019. She won the fight via unanimous decision.
Bellator Women's Flyweight World Champion Juliana faced undefeated flyweight champ,
Ilima-Lei Macfarlane, on December 10, 2020 at
Bellator 254. She won the fight and the
Bellator Women's Flyweight World Championship via unanimous decision. Juliana made her first title defense against
Denise Kielholtz on July 16, 2021 at
Bellator 262. She won the bout by split decision. Velasquez attempted to defend her title against
Liz Carmouche on April 22, 2022 at
Bellator 278. She lost the bout and the title via elbows from crucifix at the end of the fourth round. Following the bout, Velasquez's team appealed the result on the grounds of refereeing error made by Mike Beltran, but the appeal was denied by the Hawaii State Boxing Commission. In a title rematch, Velasquez faced
Liz Carmouche again on December 9, 2022 at
Bellator 289. She lost the fight via an armbar submission in the second round. Velasquez was scheduled to face Paula Cristina on November 17, 2023 at
Bellator 301. The week of the event, the bout was scrapped for unknown reasons.
Professional Fighters League Velasquez debuted with the
Professional Fighters League (PFL) at
PFL 1 on April 4, 2024 and lost the bout by unanimous decision to
Liz Carmouche in a third consecutive loss against her. Velasquez faced Lisa Mauldin at
PFL 4 on June 13, 2024. She won the fight via TKO in the second round. On February 18, 2025, the promotion officially revealed that Velasquez joined the
2025 PFL Women's Flyweight Tournament. However, Santos withdrew from the tournament and was replaced by Ekaterina Shakalova. She lost the fight via rear-naked choke in round one. Velasquez faced Skakalova in a rematch at
PFL 9 on August 15, 2025. She won the fight by unanimous decision. ==Championships and accomplishments==