De Bruyne has been an integral part of the City side for a decade since arriving from Wolfsburg in the summer of 2015, helping the club win every possible trophy under the guidance of Pep Guardiola.
The Belgian took to social media to announce his decision, stating "whether we like it or not, it's time to say goodbye".
"These will be my final months as a Manchester City player," De Bruyne posted.
"Nothing about this is easy to write, but as football players, we all know this day eventually comes.
"That day is here, and you deserve to hear it from me first.
"Football led me to all of you - and to this city. Chasing my dream, not knowing this period would change my life. This city. This club. These people... gave me everything. I had no choice but to give everything back! And guess what - we won everything."
Despite having a reduced role this season, De Bruyne departs as a Manchester City legend, having won the Champions League, six Premier Leagues, two FA Cups and five EFL Cups.
The midfielder was also named City's and the Premier League's Player of the Season on two separate occasions.
"Whether we like it or not, it's time to say goodbye," he continued.
"This will always be our home. We cannot thank the city, club, staff, teammates, friends, and family enough for this 10-year ride.
"Every story comes to an end, but this has definitely been the best chapter. Let's enjoy these last moments together."
De Bruyne's contract is due to expire on June 30th, 2025, marking his departure from the Etihad Stadium following the remaining fixtures of the season.
City are next in action against Manchester United - De Bruyne's final derby - on Sunday, April 6th.