This act takes place three years after the previous act. It opens in the Nagasaki home where Suzuki prays. Butterfly says they should pray to Pinkerton’s god, not the Japanese gods. He has not returned since the wedding, and they are running out of money. Suzuki and Butterfly disagree about Pinkerton—the latter thinks he will return, while the former does not think he will. Suzuki cries, and Butterfly describes how she imagines the event of Pinkerton’s return. They hug and Suzuki leaves the room.

Goro and Sharpless arrive and briefly talk in the garden. Sharpless goes into the house, and Butterfly is excited to see him. She offers him a pipe, prepared by Suzuki, then offers him a cigarette. Meanwhile, Sharpless tries to tell her about the letter he holds. Eventually, he reveals that the letter is from Pinkerton, but he does not share its content. Butterfly talks about Pinkerton’s promise to return in spring, noting that several springs have passed since they were married. She then notes how Goro has been trying to get her to marry someone else: Yamadori. This suitor arrives with flowers.

Yamadori and Butterfly talk about his unrequited love for her.