The former Real Madrid midfielder has penned a four-year contract with the Basque outfit after an unsuccessful stint with Valencia.
Real Sociedad has announced the signing of Sergio Canales from Valencia for an undisclosed fee.
The injury-plagued former Real Madrid midfielder had been linked with a move away from Mestalla throughout the transfer window.
Sociedad confirmed the capture of Canales on deadline day, revealing that the 22-year-old had put pen to paper on a four-year deal with the Basque outfit after passing a medical.
The arrival of Seydou Keita at Valencia allowed Sociedad to make their move for Canales, and he returns to the north of Spain, where he began his career with Racing Santander before moving to Madrid in August 2010.
Canales will be formally presented to the press Monday, after this weekend's Liga meeting with Atletico Madrid.