The two face each mother on May 2 in Las Vegas.
Pacquiao has arrived in Los Angeles with brother Bobby and adviser Michael Koncz.
He will start the first week of his eight-week workout without trainer Freddie Roach who is busy training Zou Shiming in Macau for his title fight against flyweight champion Amnat Ruenroeng of Thailand on March 7.
Roach will reunite with Pacquiao on March 9.
"Although I'm confident that I can win the fight, I will still train hard," said Pacquiao, the reigning World Boxing Organization welterweight champion.
Pacquiao's wife Jinkee is optimistic of her husband's chances against Mayweather.
"I'm not worried and very confident that Manny will win," Jinkee told The Manila Times in separate interview.
"Manny's fight is to fight of all the Filipinos who cheer and support him."