United will spend 10 days abroad, playing FC Domzale and two other unconfirmed opponents.
The trip is accompanied by friendlies at non-league Farsley FC and League One sides Walsall and Stevenage.
Pre-season will conclude for Brian McDermott's side when they welcome Germans FC Nurnberg to Elland Road, a week before the season opener.
The Yorkshiremen will report back to the club on June 27 and begin training in early July.
