Youth career Born in
Nkol Ngok, Onana joined
Barcelona from the
Samuel Eto'o Academy at the age of 14 in 2010. Because he was under 18 and a non-EU citizen, Onana had to go on loan in the 2012–13 season to the youth team of
Cornellà, before being loaned again the next season to the first-team of Vista Alegre.
Ajax in 2016 In early January 2015, it was announced that he would join Dutch club
Ajax in July 2015. The transfer was brought forward later that month. He made his debut for
Jong Ajax in the
Eerste Divisie in February 2015. In March 2019 he signed a further new contract, until June 2022. In November 2019, he said he was interested in playing in the
Premier League in England. In February 2021, Onana was banned from playing for 12 months by
UEFA after testing positive for
furosemide, a banned substance. Onana said he took his wife's medicine by mistake and Ajax joined him in appealing against the decision. The ban was reduced to nine months by the
Court of Arbitration for Sport later in June. In January 2022, he was linked with a transfer to Italian club
Inter Milan. In May 2022, he announced that he was leaving Ajax. Onana spent seven and a half years with Ajax, making 214 appearances in all competitions during his stint. In January 2023, he won the
Supercoppa Italiana against rivals
AC Milan, and also went on to win the
Coppa Italia, defeating
Fiorentina in May 2023. He played an integral role in helping guide Inter to the
2023 Champions League Final.
Manchester United After discussions with the club through the month, on 16 July 2023 it was reported that Onana had agreed personal terms with Premier League club
Manchester United for a five-year contract. Manchester United confirmed the transfer on 20 July, for an initial £43.8 million fee with Inter for the transfer of Onana, with a potential £3.4 million in add-ons, which saw Onana rejoin his former Ajax coach,
Erik ten Hag. Onana made his competitive debut for the club in the Premier League opener against
Wolverhampton Wanderers on 14 August. He kept a clean sheet as United won the game 1–0, but was at the centre of controversy after referee
Simon Hooper and VAR
Michael Salisbury opted not to award a late penalty for a foul by Onana on
Saša Kalajdžić. On 20 September, following a 4–3 defeat against
Bayern Munich in the
Champions League opening fixture, Onana said he had "let the team down" following mistakes during the match. He was then described by journalist
Guillem Balagué as "not the perfect goalkeeper but good enough for Manchester United". Ten Hag later said that Onana should be inspired by Manchester United's legendary goalkeepers
Peter Schmeichel and
David de Gea. On 24 October 2023, he saved a penalty in the 97th minute in a Champions League match which ended in a 1–0 victory against
Copenhagen, leading to his club's first win in the competition that season. A month later, Onana was heavily criticised for his performance in a 3–3 Champions League draw against
Galatasaray; he was directly blamed for Galatasaray's first two goals, which came from former Ajax teammate
Hakim Ziyech free kicks. The
BBC called it "a night of suffering for Onana", who "produced a horror show to undermine much of United's good work", while the
Manchester Evening News declared he "carelessly conceded" the first Galatasaray goal, "catastrophically fumbled" the second and "too easily beaten" for the third. He was defended by manager Erik ten Hag, who opined that Onana's stats showed him to be the second-best goalkeeper in the Premier League. At the end of his first season, he said it had taken six months for him to "feel good". The season finished with Onana winning his first trophy with United, the
FA Cup, beating
Manchester City in the final. During his second season, by December 2024 Onana had kept more clean sheets than any other Premier League goalkeeper, but was criticised for making mistakes against
Nottingham Forest and
Viktoria Plzeň. In April 2025, ahead of a game between Lyon and Manchester United, former Manchester United and current Lyon player
Nemanja Matic described Onana as "one of the worst goalkeepers in the club's history". Onana was considered to be at fault for both of Lyon's goals in a 2–2 draw, but was defended by manager
Ruben Amorim. However, Amorim then dropped Onana for the club's next match. Ahead of the
2025–26 season, Onana missed United's pre-season tour of the United States due to injury. After
Altay Bayındır started in goal for United's first two Premier League matches, Onana made his season debut in the
EFL Cup against
EFL League Two side
Grimsby Town. United were surprisingly beaten on penalties by the lower-league team, and Onana's performance was again criticised,
Loan to Trabzonspor In September 2025, it was reported that Onana was considering a loan move to Turkish club
Trabzonspor. The move was completed on 11 September. Three days later, Onana made his debut for Trabzonspor against
Fenerbahçe, conceding a goal to
Youssef En-Nesyri just before half-time following a 20th-minute
red card for
Okay Yokuşlu, as Trabzonspor lost 1–0. ==International career==