Atletico Madrid have agreed to pay Spurs £34.2m (€40m) for the 28-year-old, with Tottenham retaining a 15% sell-on clause on any future transfer. Romero's last appearance for the club came against Sunderland in April, when he left the field in tears with a knee injury that ruled him out of Spurs' final six Premier League games as the team fought against relegation.
That period was not without controversy: with Spurs in a relegation battle, Romero had planned to travel to Argentina for the final weekend of the season to watch his first club, Belgrano, play in the Primera División Apertura final, upsetting some supporters.
He ultimately returned to England in time to be present for the 1-0 win over Everton that secured survival and a second consecutive 17th-place finish.
Announcing his exit on Instagram, Romero reflected honestly on his time at the club.
"I know I wasn't perfect," he wrote. "But one thing gives me peace: I always gave everything. I defended this shirt with pride and with all my heart."
He also spoke about the ambition that brought him to England in 2021 from Atalanta.
"When I arrived, I had a clear dream: to leave my name in this club's history," he added. "I knew the only way was through hard work, sacrifice and achieving something that had seemed so difficult for so long: lifting a trophy again. And we did it.
"I'm leaving the club, but a part of my heart will always remain here. Once I was one of you. Today, I leave as one of you forever. With all my love and respect. Thank you for everything."
Romero made 156 appearances during his time at Tottenham, becoming a defensive mainstay and later club captain. His standout moment came in the 2025 Europa League final win over Manchester United, which ended the club's 17-year wait for a trophy and saw him named man of the match.
He now joins Diego Simeone's Atletico Madrid, who beat off competition from elsewhere in Europe to complete a deal that had been pursued for much of the summer.