Monreal last played for Real Sociedad in the Spanish La Liga but missed the entirety of the 2021/2022 season due to a knee injury.
That knee injury has taken a toll on Monreal, who has now announced that he will not be making a return to the game.
Monreal started his career at Osasuna and later moved to Malaga before making the switch to England.
Monreal joined Arsenal from Malaga in January 2013 and went on to appear 250 times in all competitions, scoring 10 goals and winning three FA Cups and three Community Shield trophies.
He returned to Spain in 2019 with Real Sociedad for two years and won a Copa del Rey.
On the international stage, Monreal won 22 caps for Spain and was an unused member of their 2018 FIFA World Cup squad.
He posted on Instagram: "Thirty-six years playing football, 16 as a professional. Squeezing my body and taking it to limits that I would never have imagined.
"My knee sends me a message… loud and clear; I cannot continue! Do I get mad? NO! I listen to it and accept the situation and thank it for everything.
"A stage is over. Another starts. I'm happy and feeling good. One more time… I FEEL GOOD!!! And that gives me peace of mind.
"Life is a gift and I like to be grateful. Thank you Osasuna, Spain, Malaga, Arsenal, Real Sociedad for letting me cross your paths. What good years…."
