Tosin Adarabioyo was born in London but raised in Manchester, where he joined Manchester City's academy at the age of five after being spotted at a local five-a-side tournament. He progressed steadily through the youth ranks, captaining the under-18 side and eventually earning promotion to the first team under Pep Guardiola ahead of the 2016–17 season.
At City, Adarabioyo became the then-youngest player to start a UEFA Champions League match for the club, doing so at just 19 years and 73 days old. With first-team opportunities limited by a strong senior defensive unit, he went out on loan to West Bromwich Albion and Blackburn Rovers, making over 30 league appearances in each spell and scoring three goals for Blackburn in the 2019–20 Championship season.
In 2020 he joined Fulham on a permanent deal, where he established himself in the Premier League and played a key role in the club's 2021–22 Championship title win and immediate promotion back to the top flight. He left Fulham on a free transfer in the summer of 2024, signing a four-year contract with Chelsea, for whom he scored in an 8–0 Europa Conference League victory over FC Noah in November 2024.
An athletic, ball-playing centre-back who stands at 6 ft 5 in, Adarabioyo combines aerial dominance with the ability to distribute from deep. He represented England at youth level on 14 occasions across the under-16 to under-19 age groups but is yet to earn a senior international cap, and also remains eligible to represent Nigeria through descent.