The Bundesliga champions have paid a fee in the region of £7.8m to loan the 27-year-old for the season, in addition to matching the entirety of his £200k per week wages.
The agreement contains a £110m option-to-buy clause ahead of the 2020/21 season.
Upon signing for Bayern, Coutinho said: “For me, this move means a new challenge in a new country with one of the best clubs in Europe.
“I'm very much looking forward to that. Like FC Bayern, I have big ambitions and I'm convinced that I can achieve them together with my new teammates.”
FC Bayern CEO Karl-Heinz Rummenigge added: “We've been working on bringing in Philippe Coutinho for quite some time and we're very happy that we’ve been able to complete this transfer.
“Our thanks go to FC Barcelona for agreeing to the transfer. With his creativity and outstanding skills, Philippe is a player who will immediately strengthen our attack.”
Coutinho joined Barcelona from Liverpool for £120m in January 2018, a transfer that at the time made him the world’s third most expensive player, behind only Paris Saint-Germain forwards Neymar (£200m) and Kylian Mbappé (£123m).
However, the Brazil international struggled to hold down a place in Ernesto Valverde’s first-team and this summer came close to joining both Arsenal and Tottenham on a short-term deal.
“FC Barcelona would like to thank to publicly thank Philippe Coutinho for his commitment and dedication wishes him all the best in this new stage of his career,” the Spanish club said in a short statement published to their website.
He leaves Barcelona having made 76 appearances in all competitions for the Catalan club, scoring 21 goals.
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