In 2020, he reached the Moto3 Junior World Championship, and in his first season, he was crowned Champion. Thanks to this incredible result, Aspar Team added him to their ranks for 2021, and the rookie didn’t disappoint. After many excellent performances, Guevara finally got himself onto the podium at the Americas GP, where he was declared the race winner following a red-flagged race.

In his second season on the World Championship circuit, the Spaniard was considered by some to be an outside bet for the 2022 Moto3 title, but he excelled. He secured the World Championship with two races to spare thanks to victory number six of the year in Australia and signed off from the lightweight class with a win in Valencia, which gave him a sweep of the year's four Spanish rounds.

He continued to do the Aspar GASGAS team colours in 2023 after making the jump up to Moto2. In his first season in the intermediate category, the young Spaniard struggled to make an impact and only achieved a sixth place as his best result. In 2024, he struggled to secure regular top-10 finishes, but did manage to secure a podium in Malaysia, taking third place.

With two years of Moto2 experience to his name, he'll be one to watch in 2025 as he embarks on a new journey with the BLU CRU Pramac Yamaha Moto2 Team.

In 2025, Izan Guevara delivered a breakthrough season with the BLU CRU Pramac Yamaha Moto2 squad, highlighted by a dominant victory at the Valencia Grand Prix – the team’s first-ever Moto2 win and his own maiden triumph in the intermediate class. As a reward, and in fulfillment of a bet with Team Principal Gino Borsoi, Guevara earned a coveted end of year MotoGP opportunity, riding Jack Miller's YZR M1 during Yamaha's private post season test at Circuit Ricardo Tormo. This wildcard-style experience offered him his first taste of premier class machinery and served as added motivation heading into the 2026 season.