Choudhury has represented England at under-21 level and, after receiving his Bangladeshi passport in late 2024, made the decision to play for the Bangladesh national team.

[12] He made his debut in the Football League later that same day, coming on as a 77th-minute substitute for Tom Naylor in a 0–0 draw with Walsall at the Pirelli Stadium.

[15] Choudhury made his first-team debut for Leicester City on 19 September 2017, coming on as substitute in a 2–0 win against Liverpool at home in the third round of the EFL Cup.

[24] On 10 August 2022, Choudhury joined Championship club Watford on loan for the season, with the option to make the move permanent the following summer.

[27] On 26 May 2018, Choudhury made his debut for the England national under-21 football team, coming on as a substitute during the 2–1 win against China under-21 in the 2018 Toulon Tournament.

[29] On 27 May 2019, Choudhury was included in England's 23-man squad for the 2019 UEFA European Under-21 Championship[30] but was shown a straight red card for a reckless tackle during the second half of the opening 2–1 defeat to France in Cesena.

[34] Choudhury obtained his Bangladeshi passport on 23 August 2024,[35] and on 24 September 2024, the English Football Association issued him a No Objection Certificate (NOC), allowing him to officially represent Bangladesh.

[37][38] On 9 February 2025, Hamza was included in the preliminary squad for Bangladesh's 2027 AFC Asian Cup qualification – third round match against India.

[45] After winning in the FA Cup Final in 2021, Choudhury and his teammate Wesley Fofana both celebrated draped in the flag of Palestine, during the 2021 Israel–Palestine crisis.