By SABC Sport
7th July 2023
The 26-year-old German defender spent three seasons at Elland Road, making 77 appearances.
Koch said on Instagram: "Dear LUFC fans, at this point I look back on three wonderful and exciting years in Leeds.
"To play for Leeds United and in front of you unforgettable fans, to defend for these colours, to celebrate with you, to even lead the team onto the pitch as captain, was a special honor and pleasure during the last three seasons.
"All the moments I have experienced together with you and especially at Elland Road, great victories and bitter defeats, have made me the person I am today.
"These are impressions and feelings that cannot be put into words and that have made me very proud and happy that my path as a professional footballer has led me to this club. I have taken Leeds United into my heart.
"I have met many, many great people here up to this point, and my greatest thanks go to them. To all the people in charge at the club, all the staff, my coaches, my teammates and, of course, you fans!
"I wish the club, the city and all of you only the best and hope that you will remember me well. I will definitely do so. Thanks for everything so far! Yours Robin."