Ling Ling, 15, a male giant panda loaned to Mexico City's Chapultepec Zoo in late January, returned Wednesday to Tokyo's Ueno Zoo after his mission to mate with three female pandas there.
It was the first time a panda had been absent from the Tokyo zoo since the first one was donated by China in 1972. Ling Ling, the zoo's only panda, will be ready for visitors this weekend, the beginning of the Golden Week holiday season.
Ling Ling was sent to the Mexico zoo in January in the hope he would mate with the three female pandas there.
But the attempt failed after Ling Ling apparently became unsettled by the change.
In March, officials tried artificial insemination. The results will be known in summer, Ueno Zoo officials said.
Ueno Zoo said that if cubs are born in the latest attempt, they will be shared by the two countries.
The first would go to Tokyo and the second would remain in Mexico.
The cubs will stay in Mexico in the immediate term because it takes about 18 months for a panda cub to become independent of its mother.