The Spaniard impressed his new team-mates during his first practice, and the wing-back and goalkeeper are both confident he will make an impact at the Allianz Arena
The Spain international signed a five-year deal with Bayern earlier this week to complete his €40 million (£32m) move from Athletic Bilbao, and he has already impressed his new team-mate during his short time at the club.
"I've seen a bit of him in the past, and I reckon he's a very good footballer," Lahm was quoted as saying on the club's official website.
"[Head coach Jupp] Heynckes introduced him to the rest of the team and then he went out and just played football. He fitted in straight away. My initial impression is that he's quality. He'll help us a lot."
Shot-stopper Manuel Neuer was equally pleased with the versatile midfielder's arrival at the club, and stressed that Javi Martinez will need time to find his best form in his new surroundings.
"It's great that he's here. He lost his first practice match, but he threw himself into it and won a lot of balls in the air.
"He was very good, he's still very young, and he's starting out on a great career. There's a lot coming at him from all directions, a new club, a move abroad. He'll need time before we can say he's really arrived. He's not been signed just for one season, but for the long term."
The 24-year-old could make his official Bayern debut against Stuttgart on Sunday.