"We are sure that, by signing Juan Bernat, we will have made a very good investment for the future. He's very welcome at Bayern Munich."
The Spain Under-21 international becomes the third Spanish player on Bayern's books, joining Thiago Alcantara and Javi Martinez in the service of Pep Guardiola.
"I'm really happy that I will be able to play at this club," he said after signing his contract with the Bavarians.
"Bayern are one of the biggest clubs in Europe and the world and I'm really, really pleased to play in a team with players like (Philipp) Lahm, (Manuel) Neuer, (Bastian) Schweinsteiger, (Arjen) Robben and (Franck) Ribery, and to have Pep Guardiola as coach.
"I will give everything to be successful with this club."