Pique, 35, says Saturday's match against Almeria in LaLiga will be his last at Camp Nou for the Catalan club after 14 years in the first team following his return from Manchester United in 2008.
Barca then travel to Osasuna next week for their final fixture before the World Cup in Qatar.
"The last few weeks, months, people have been talking about me," Pique said in a video posted across social media. "Until now, I have not said anything, but now I want to be the one who is talking about me.
"Like many of you, I have always been a Barcelona fan. I was born into a football-loving family. From a very young age, I did not want to become a footballer, I wanted to play for Barca.
"Recently, I have thought a lot about that kid. If he had been told he would fulfil all his dreams -- that he would play for Barca, that he would win every trophy possible, that he would be a European and world champion.
"That he would play with the best players in history, that he would become one of the team's captains. ... Football has given me everything. You, the fans, have given me everything. And now my childhood dreams have been fulfilled, I want to tell you that I've decided that now is the time to bring this journey to its end.
"I have always said that after Barcelona there will be no other team, and that is 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 and transmit my love for the club to my kids, like my family did with me. And you know me, sooner or later I will be back. See you at Camp Nou. Visca Barca, always and forever."
Culers, us he de dir una cosa. pic.twitter.com/k3V919pm1T— Gerard Piqué (@3gerardpique) November 3, 2022
Pique's grandfather was on the board at Barcelona, and Pique joined the club's academy in 1997 before leaving for Man United in 2004.
After four years in Manchester, which included a season-long loan back in Spain with Real Zaragoza, and 23 first-team appearances for the English side, he returned to Barca in 2008.
Under Pep Guardiola, he was part of the side that won the treble in the 2008-09 season, and he will depart having won eight LaLiga titles and three Champions Leagues, among many other trophies.
He also won the World Cup in 2010 and the 2012 European Championship during a nine-year career with Spain, during which time he earned 102 caps before retiring from international football after the 2018 World Cup in Russia.
Despite being fifth choice in his position, with Ronald Araujo and Eric Garcia also ahead of him, Pique has still made nine appearances in all competitions so far this season because of injuries elsewhere.
However, after the 3-3 draw against Inter Milan last month, when Pique was singled out for criticism, left-back Marcos Alonso has been used in front of him in defence, prompting him to consider retiring midseason despite having a contract until 2024.
Barca had told Pique in the summer that minutes would be hard to come by this season as they looked to either move on or reduce the salaries of some of the veterans, including Sergio Busquets and Jordi Alba.
Pique, Busquets and Alba have all readjusted their salaries and agreed to reductions and deferrals on their wages at various points in recent years to help the club deal with a difficult financial situation.
However, with deferred payments due, their salaries take up a large chunk of Barca's budget in comparison with how many minutes they have been playing under Xavi this season.
Sources contacted by ESPN were not immediately able to confirm whether Pique's retirement meant he had agreed to give up the money owed to him or whether an agreement has been negotiated with Barca.
Pique, who will turn 36 in January, already has a number of other interests outside of football. Through his company, Kosmos, he has revamped the Davis Cup tennis tournament, and he is also the owner of second-division side Andorra.
He has previously said that he plans to run for Barca president once he retires, although in recent years he has suggested that, although that remains an option, it is not something he will definitely pursue.