Suzuki made his Grand Prix debut in the 2015 Moto3 World Championship with the CIP team, riding a Mahindra alongside Remy Gardner. He scored nine points across the season, with a best result of tenth at Silverstone. In 2016 he remained with CIP, now branded as CIP-Unicom Starker, partnering Fabio Spiranelli. Suzuki improved to 16 points over seven scoring finishes, with a best result of 11th at Sachsenring.
In 2017, Suzuki joined Sic58 Squadra Corse alongside Tony Arbolino. The move proved transformative: Suzuki amassed 71 points, with a season-best fourth place at his home Grand Prix of Motegi. He continued with Sic58 in 2018, again scoring 71 points, this time partnered with Niccolò Antonelli.
The 2019 season was the best of Suzuki's career. He won from pole position at the San Marino Grand Prix at Misano and finished second at Jerez, where teammate Antonelli took the win — giving Sic58 a historic 1–2 in the race. Suzuki finished the year with 124 points and eighth in the championship.
In 2020 he won again at Jerez during the second race of that venue and finished third at San Marino, ending the year 12th in the standings with 83 points. The 2021 season brought a step back: no podiums and 76 points for 14th overall, though Suzuki remained one of the team's more consistent performers relative to teammates over his five years at Sic58.
Joining Leopard Racing for 2022 alongside championship runner-up Dennis Foggia, Suzuki enjoyed his statistically best season in Moto3. He scored three podium finishes — third at Mugello, third at Barcelona, and second at the Austrian Grand Prix in Spielberg, where he finished less than a tenth of a second behind compatriot Ayumu Sasaki — and accumulated 130 points for seventh in the championship.
The 2023 season opened promisingly when Suzuki won in wet conditions at the Argentine Republic Grand Prix, his third career victory. However, five retirements and an injury sustained at Mugello disrupted his campaign, and he was replaced by Adrian Fernandez after the Japanese Grand Prix. He was retained at Leopard by Jaume Masià as his teammate.
Suzuki moved to Liqui Moly Husqvarna Intact GP for his final season, pairing with Collin Veijer. Results did not improve relative to his Leopard years: his best finish was a sixth place at the Grand Prix of the Americas, and he ended the season 14th with 91 points. Finding no seat for 2025, Suzuki announced his retirement from motorcycle racing on 8 February 2025.
Over ten seasons and more than 180 Grand Prix starts, Suzuki compiled three race victories and established himself as a reliable and experienced competitor in Moto3. His 2022 campaign at Leopard Racing represented his career peak in terms of championship position and points, and his 2019 win from pole at Misano remains his most celebrated result. He was among the last Japanese riders to maintain a sustained Moto3 presence across an era when Japanese entries in the entry-level GP class became increasingly rare.