Olascuaga turned professional in 2020 and compiled a record of 5–0 before facing unified
light-flyweight world champion
Kenshiro Teraji at the
Ariake Arena in
Tokyo on 8 April 2023, losing via ninth-round stoppage. At the same venue, he got back to winning ways in his next fight, stopping
Giemel Magramo in the seventh round on 18 September 2023. Next Olascuaga received another shot at becoming a world champion, knocking out
Riku Kano in the third round at
Ryōgoku Kokugikan in Tokyo to win the vacant
WBO flyweight title on 20 July 2024. He made his first defense against
Jonathan González at Ariake Arena in Tokyo on 14 October 2024. The fight ended in unusual circumstances when his opponent refused to continue the bout after suffering a cut due to a clash of heads in the first round. Initially ruled a no contest, the result of the fight was changed to a technical knockout win for Olascuaga two weeks later. Olascuaga's second title defense was a unanimous decision success over
Hiroto Kyoguchi at Ryōgoku Kokugikan in Tokyo on 13 March 2025. He stopped Juan Carlos Camacho Jr. in the second round at
Fontainebleau Las Vegas in
Winchester, Nevada, USA, on 11 September 2025, to retain his title for a third time. Making the fourth defense of his title, Olascuaga defeated Taku Kuwahara via fourth round technical knockout at Ryōgoku Kokugikan in Tokyo on 17 December 2025. Olascuaga is scheduled to make the fifth defense of his WBO flyweight title against Jukiya Iimura on March 15, 2026, in Yokohama, Japan. ==Personal life==