The 39-year-old American athlete, who is visiting Leicester, Liverpool and London in March, was jailed for attacking his ex-girlfriend in 2012.
The charity said he has "never shown remorse" and his appearances would condone domestic violence.
The show's promoter said Mayweather was "willing to learn from his mistakes".
Shane Whitfield, from Kong Events, said the boxer "acknowledged the seriousness of previous events" and was "openly willing to learn from his mistakes and look to his future".
The statement continued: "We are aware that Floyd Mayweather has made mistakes in the past and we are not condoning that.
"Mayweather actively supports numerous charities, and his work with these organisations displays a generous and considerate nature.
"We are confident his UK tour will give him the opportunity to speak openly and honestly about his past, and how is he working towards a positive future."
Polly Neate, chief executive of Women's Aid, said: "Mayweather has never shown remorse for his serious and sustained attacks against women and has even made excuses for his crimes.
"This is not acceptable. He is still considered a hero, and his UK tour will undoubtedly be very lucrative.
"What message does this send out about violence against women?
"If we do not hold perpetrators to account - especially high-profiles ones like Mayweather - we will never drive the culture change we need to keep women and girls safe."
In December 2011, he was sentenced to 90 days in prison for attacking his ex-girlfriend Josie Harris.
He also pleaded guilty to two counts of domestic violence in 2002 and was given a suspended sentence for assaulting two women in a Las Vegas nightclub in 2004.
Individual tickets for "The Undefeated Tour" cost between Â£40 and Â£1,000.
Mayweather will meet fans and speak for 45 minutes to audiences at Leicester's Athena, Indigo at the O2 in London and at The Auditorium in Liverpool.
The boxer embarked on a larger "European Victory Tour" around venues in the UK last year.
Mayweather won world titles at five weights and retired with an unblemished record.
Boxer Floyd Mayweather's "very lucrative" tour to England sends out the wrong message about domestic violence, charity Women's Aid has said.