The Victorian Civil and Administrative Tribunal handed down its verdict on April 28.
The centre operated women-only sessions for several years but dropped them after its $13.8-million redevelopment was completed in September 2007.
The women-only swimming sessions will be staffed by women and run from 8-10pm on Sundays.
Handing down her decision, VCAT deputy president Cate McKenzie said the YMCA had received expressions of interest from more than 100 local women.
Letters of support were also received from the Centre for Multicultural Youth, the Ascot Vale Network (a group of service providers) and the Active Young African Program.
Ms McKenzie said a 2008 survey found service providers and Ascot Vale residents identified a need for women-only swimming sessions.
She said the decision aimed to correct a disadvantage faced by the large number of Muslim women living in Ascot Vale and neighbouring suburbs.
"It is clear from all the material before me that Muslim women are unable, because of their cultural and religious values and beliefs, to participate in swimming sessions in mixed male/female company.
"For them, it is not an option to attend the Ascot Vale Leisure Centre during its public opening hours when it is open to women and men alike.
"The only way to provide accessible opportunities to swim and learn to swim for these women is at times when the centre would be open to and staffed by women only."
YMCA spokeswoman Shona Eland said the swimming sessions would begin in July or August after $15,000 worth of blinds were in place to cover windows.
She said about 100 people were expected to attend weekly.
"We really want to make sure the programs we offer target the diverse community we have.
"'The community groups around Ascot Vale have been the ones working at [women-only sessions] and driving it to return."
The co-ordinator of the Jesuit Social Services African Program in Flemington, Cathy Guiness, said the service had helped introduce women-only sessions in Kensington in the past.
"We know how big the need is and how very successful swimming programs are," Ms Guiness said.
"It's important because there are really not a lot of physical activities available for Muslim women.
"They really appreciate the opportunity to learn to swim and to have social opportunities they can enjoy."
Nick Mac Hale of the Centre for Multicultural Youth's sports and recreation team said several municipalities had run successful women-only swimming sessions for years.
"Women from newly arrived backgrounds would have the lowest amount of participation in any sport in the last five years," he said.
"It just opens up the accessibility of a local leisure centre to the whole community. It's great that Ascot Vale has stood up and said, 'Yes, we need this'."