"On (next) Saturday, I will play my last match with Juventus," Buffon told the media on Thursday.
"Up until 15 days ago, it was certain and well-known that I would stop playing.
"Now I have received some proposals and exciting challenges, both on the field and off it.
"The most important for staying on the pitch was proposed to me by [Juventus chairman Andrea] Agnelli.
"Over the next three days, full of emotion, I will after two or three days of reflection make a definitive decision.
"I believe this is the best way to put an end to my great adventure."
Buffon, 40, joined Turin's Juventus in 2001, and has led the team as captain since 2012, helping Juventus win seven consecutive Serie A championships, and four national "Coppa Italia" trophies.
On Saturday afternoon, Juventus will face Hellas-Verona in Turin in the 38th and last game of the regular season, after winning its seventh title last Sunday.
Named captain of the national team in 2011, Buffon is the most capped Italian international with 176 international appearances, and the fourth-most capped footballer of all time.
During the press conference, he confirmed he would leave, pointing out that the Azzurri "have many relevant young goalkeepers, who need to gain experience."
His farewell at international level might come on June 4, when Italy hosts a friendly against the Netherlands in Turin.
The goalkeeper announced his retirement from international competition in 2017, after Italy failed to qualify for the 2018 FIFA World Cup, but later he agreed to stay for friendlies in 2018.
Buffon unveiled no clear plans for his future yet, saying he would take a decision "on several interesting proposals" over the next week.
He was named goalkeeper of the year by FIFA in 2017. In 2011, the International Federation of Football History and Statistics (IFFHS) also named him the world's best goalkeeper of the 21th century and in 2012 he was named the best goalkeeper of the past 25 years.