The 18-year-old has signed a contract until June 2028 but will remain at River before moving to the Etihad Stadium in January next year.
Echeverri, who only turned 18 on January 2, has already made six appearances for the Buenos Aires giants.
Former City defender Martin Demichelis, who is the manager at El Monumental, gave him his debut in June 2023 where he claimed an assist in a 3-1 victory over Instituto Cordoba.
He then captained Argentina at the Under-17 World Cup in November and December and scored a hat-trick in a 3-0 quarter-final victory over Brazil.
However, they were eliminated on penalties in the semi-finals by Germany but Echeverri picked up the bronze ball as the tournament’s third top scorer.
In total he has made 23 appearances for Argentina’s under-17s, scoring 13 times and has also trained with the senior national team.
Echeverri follows in the footsteps of 2022 World Cup winner Julian Alvarez who moved to City from River in 2022 and becomes the latest in a long line of Argentinians to join the Club.
Everyone at Manchester City is looking forward to welcoming Claudio to the Club and we wish him the best of luck in his remaining time with River.