First up are Bottesford Town, former club of United's third choice goalkeeper Sam Slocombe, who will host the Iron at Birch Park on Saturday July 10. The match will kick-off at 3pm.
United will head to the Hawthorns to take on Brigg Town on Wednesday July 14, with a 7pm start.
The final match announced on Friday is a trip to Winterton Rangers, with that game taking place at West Street on Saturday July 17. Kick-off will be at 3pm.
The Iron now have four confirmed friendlies during pre-season, with the League One side Sheffield Wednesday heading to Glanford Park on Saturday July 24.