Town will play a friendly against League of Ireland side Finn Harps on Tuesday July 7.
The game will take place at Harps' Finn Park ground with kick-off at 8.00pm.
Harps, who are based in County Donegal and were founded in 1954, are expecting a near capacity 5000 gate for the game.
They are currently 10th in the FAI First Division after being relegated from the Premier of the final day of last season.
Blues are also closing in on finalising a friendly with Cork City, also for July, although a date and kick-off time have yet to be confirmed.
Town's pre-season fixture programme currently reads: July 7 Finn Harps (a); July 8 Hadleigh (a); July 15 Brentford (a); July 22 Southend (a); July 28 Charlton (a). Blues are also playing Colchester at Portman Road in Fabian Wilnis' testimonial on July 25.
