The 20-year-old, regarded as one of Australia's brightest young pace prospects, will pull on an Irish shirt after an agreement between Cricket Australia and Cricket Ireland.
Cummins has already been in Belfast as a non-playing member of the Australia A squad that completed a 93-run win over Ireland in their four-day game at the weekend. But following discussions, it was agreed to allow Cummins, who has not played since October last year due to stress fractures in his back, to appear in two matches over the next three days.
Cummins will play in the match against the Marylebone Cricket Club before switching allegiance two days later to play against Ireland Under-19s, who are preparing for their World Cup qualifiers in August.
"It's a fantastic opportunity for the young players to play with and against someone of the calibre of Pat Cummins," Ireland Under-19 coach Ryan Eagleson said.
"It'll be a wonderful experience for them and help in their cricketing development. I know they're all excited and can't wait for the matches to start."
Cummins burst on to the international scene in November 2011 when he was man of the match in his only Test as Australia clinched a series-levelling win against South Africa in Johannesburg.
Injury has since prevented Cummins from adding to his single cap, during which he claimed six for 79 in the second innings before hitting the winning runs.