The 33-year-old has signed a four-year contract with Camp Nou that includes a €500 million release clause.
The Catalan giants announced on Saturday that they had reached an agreement in principle with Bayern for Lewandowski’s transfer, and the striker has since passed his medical before joining his new teammates on the club’s preseason tour in Miami.
He has arrived in Miami to join his new teammates as part of Barcelona’s four-match tour of the United States.
“I’m finally here. I’m delighted to be at Barca,” Lewandowski said.
“The last few days have been very long, but the deal is done and now I can focus on a new chapter and challenge in my life.
“I’ve always wanted to play in La Liga and for the big clubs.
“I’m here to help Barca get back to the top and win as many titles as possible.”
“I was speaking with Xavi and from the beginning I know [what’s been on his] mind, his ideas. It was easy for me to decide to come to Barcelona because I’m the guy who wants to play, who wants to win, and I think that with Xavi it’s very possible.
“He knows exactly how to coach Barcelona because he was an amazing player and now he’s also a very good coach. He has an amazing future and I want to be a part of this as well.”
Lewandowski won 11 trophies at Bayern including three DFB-Pokals, one Champions League, and one Club World Cup.
Lewandowski leaves Bayern as the club’s second-highest scorer of all time, trailing only Gerd Muller, with 344 goals in 375 appearances across all competitions, including 40 goals in each of the last seven seasons.
On Sunday, the striker could make his non-competitive debut for Barcelona against La Liga rivals Real Madrid in a pre-season friendly in Nevada.