The move, completed just ahead of the Turkish transfer window deadline on Friday, comes after a difficult period for the 29-year-old Cameroon international, who has seen his position at Old Trafford slip following a string of inconsistent performances and a poor start to the current campaign.
Onana's transfer does not include a loan fee or an option to buy, and Trabzonspor will cover his full wages for the duration of the loan, sources revealed. The deal remains subject to international clearance and registration.
Signed from Inter Milan in July 2023 for 47.2 million pounds, Onana was initially brought in by former manager Erik ten Hag to replace long-time United shot-stopper David de Gea. He quickly became the club's first-choice keeper and went on to make 102 appearances, playing a key role in United's 2024 FA Cup triumph.
However, Onana's time at United has been marred by costly errors in key matches. His performances came under increasing scrutiny, and he ultimately lost his starting spot this season. He made just one appearance so far - a shock Carabao Cup defeat to League Two side Grimsby Town, which only intensified doubts about his form.
With Onana sidelined, new signing Altay Bayindir has taken over the gloves, starting in all three of United's opening Premier League fixtures against Arsenal, Fulham, and Burnley - although United have yet to keep a clean sheet.
"We would like to wish Andre good luck. The move has been completed ahead of the Turkish transfer window closing on Friday," said United in a brief statement.