Leona Maguire and Stephanie Meadow both have lunchtime tee times on the opening day of the final women's Major of the year.
Muirfield hosts the Women's Open, barely five years after the club voted to admit women members for the first time.
Maguire goes out just before 12.30, while Meadow tees off at ten-to-2.
Having retrieved his clubs following an airline mix-up, Shane Lowry will be among the later starters for the opening round of the Wyndham Championship on the PGA Tour in North Carolina.
The former Open Champion tees off at 6pm, Irish time.
Celtic Manor is the venue for the Cazoo Open, which gets underway this morning.
Niall Kearney, Cormac Sharvin, Paul Dunne and Jonathan Caldwell are all involved in Newport.
Meanwhile, there has been criticism of the decision of 11 LIV golfers to file an anti trust lawsuit against the PGA Tour to have their suspensions revoked.
The group includes Phil Mickelson and Ian Poulter, who want to line up in PGA Tour events.
PGA Tour pro Will Zalatoris says the LIV golfers who wan't back in are looking for the best both worlds.