"Bernat is an extraordinary young player who we've been watching for a long time," said sporting director Matthias Sammer.
"He is quick, good in the challenge and positive going forward. We are sure we've made a very good investment."
Bernat joins recent Bayern signings, striker Robert Lewandowski from Borussia Dortmund and midfielder Sebastian Rode from Eintracht Frankfurt.
"Bayern are one of the greatest clubs in the world," said the Valencia-born Bernat.
"I'm delighted to play alongside [Philipp] Lahm, [Manuel] Neuer, [Bastian] Schweinsteiger, [Arjen] Robben and [Franck] Ribéry and to have [Pep] Guardiola as my coach."
Bernat made 51 La Liga appearances for Valencia and featured in the Spain squad that won the 2012 European Under-19 Championship in Estonia.
(Reporting by Tony Goodson, editing by Tony Jimenez)
Share
