Michelle Finn and Thomas Barr are the first Irish competitors to see action at the World Championships which get underway on Friday in Doha.
Finn goes in the second heat of the women's 3000-metre steeplechase just after 5pm, Irish time while Barr is in the first heat of the men's 400-metre hurdles after 6.30.
Donegal Mark English goes in the 800m heats and Brendan Boyce in the 50k walk on Saturday.
Having just missed the qualifying standard his season Mark eventually received an invite last weekend to be part of the Irish team which is under the management of Letterkenny's Teresa McDaid.
Mark is due to race at 3.15pm Irish time while Brendan will be on the road at 9.30pm.
A night-time schedule has been favoured in Doha to avoid the oppressive daytime heat, while the stadium has been fitted with air conditioning for athletes and supporters.
Meanwhile Downings man John Cronin is a Track Referee in Doha. John, who is a former Glenree AC National Track champion has also been selected to officiate at the 2020 Olympic Games in Tokyo.