The 35-year-old has chosen Saturday's La Liga encounter against Almeria to be his last for the club.
Pique started his career in Barcelona's famed La Masia academy before joining Manchester United.
He returned to Barcelona in 2008 and has been a mainstay at the back ever since, helping them win three Champions League trophies, eight La Liga titles, seven Copa del Reys among numerous other honours.
Pique also became a World and European champion with Spain in his time with Barcelona, amassing 102 caps for his country.
In a video posted on his social media, Pique said: "The last few weeks, months, lots of people have been talking about me.
"Until now, I haven't said anything. But now, I want to be the one talking about me.
"Like many of you, I've always been a Barca fan. I was born into a football-loving family of Barca fans. From a very young age I didn't want to become a football player, I wanted to be a Barca player.
"I've been thinking a lot about that kid recently, about what little Gerard would have thought if he'd been told that all his dreams would come true. That he would make it to Barca first team, that he would win every trophy possible, that he would become European champion and world champion. That he would play alongside the best players in history, that he would make friends for life.
"It's been 25 years since I joined Barca. I left, and I came back. Football has given me everything, Barca has given me everything. You, Culers, have given me everything.
"I want to tell you that I've decided that now is the time to bring this journey to its end. I've always said that there would not be any other team after Barca, and that's how it will be. This Saturday's game will be my last at Camp Nou.
"I will become a regular fan, I will support the team.
"I will pass my love for Barca to my children, like my family did with me. And you know me, sooner or later, I'll be back. I'll see you at Camp Nou. Long live Barca, always."
