On 22 June 2012, Alba signed a five-year contract with Barcelona for a transfer fee of €14 million. He made his official debut on 19 August, playing the full 90 minutes in a 5–1 home win against Real Sociedad.
Alba scored his first goal for the Blaugrana on 20 October 2012, the opener in a 5–4 win at Deportivo de La Coruña, and scoring an own goal. In the following game, at home against Celtic in the Champions League group stage, he found the net in the 93rd minute of a 2–1 win.