Messi said the 2026 World Cup had taken a significant physical and emotional toll, ultimately convincing him that the time was right to bring his international career to an end.
"The last World Cup was too much for me," Messi said. "While I want to stay here forever, I feel like it's the right time."
The forward reflected on Argentina's pursuit of another World Cup triumph and the demands of their campaign, particularly the meeting with England.
"We dreamed of being world champions again, we came so close," he said. "We gave it our all; the match against England was incredibly draining for us, both physically and emotionally. The truth is, we barely made it."
Messi's decision brings an emotional conclusion to a remarkable international career that began more than 20 years ago. He acknowledged the difficulty of saying goodbye to a team he had represented throughout some of the highest and lowest moments of his career.
"It was a great honour to wear this jersey for over 20 years," he said. "Even in the worst moments we've faced, I never stopped fighting, never stopped giving my all, and never stopped being there.
"Not coming back is going to be a huge pain."
The 39-year-old also revealed that his thoughts were with his father as he reflected on the end of his time with Argentina.
"It's hard to say anything today; there are so many emotions, so many things are going through my mind," Messi said. "The first thing I think of is my dad. All I can do is express my gratitude, as I said in my farewell letter."
Despite the disappointment of walking away, Messi leaves international football having achieved the honours that once appeared beyond his reach.
He credited his Argentina team-mates for helping him fulfil his childhood ambition of becoming a world champion, while also celebrating the Copa America and Finalissima triumphs he shared with the squad.
"I want to thank my teammates for the time I shared with this group, who helped me fulfil my childhood dream of being a world champion, a champion of the Americas, a champion of the Finalissima, a champion of everything we played for," he said.
"It was an enormous honour to share the field with them, both on and off the field.
"I was ready to compete against anyone because I knew I had warriors by my side who would give their all."
Messi admitted that, despite his decision, part of him would always want to continue representing Argentina.
"I swear I'd like to come back for the rest of my life, because playing for the Argentine National Team is the most wonderful thing that can happen to you," he said.
But after more than 20 years of carrying the expectations of the national team and experiencing both heartbreak and historic success, Messi believes the time has come to step away.
