Tens of thousands of women will take to the streets of Dublin and Cork later this morning for the Flora women's mini marathon.
Motorists are being advised that some roads will be closed around both city centres during the morning and afternoon.
Participants are also being urged to use public transport where possible.
Meanwhile, family and friends of murdered Jill Meagher will run the mini-marathon today in the capital, to raise funds for the Dublin Rape Crisis Centre.
The 29-year-old died last September after she went missing from a suburb of Melbourne.
A man has been charged with her rape and murder and will appear in court on June 11 in Melbourne.