Arsenal confirmed Merino’s transfer to London after paying a set price of £30 million plus variables for the midfielder. Merino signed a four-year contract until 2028, with the option to extend.
The Spanish international played 242 matches for Real Sociedad, scoring 27 goals, providing 30 assists.
Merino spent a season on loan at Newcastle United in the Premier League, scoring twice in 25 appearances.
Watch: Mikel Merino’s Newcastle United stint
Photo: Cesar Cebolla / Pressinphoto / Icon Sport