Thrumster Mains Broch has had a long history of investigation. It was subject to a very early archaeological excavation in the early 1800s. A summer house was put into the west side of the wall around the same time.
In 2011 AOC archaeology in conjunction with Yarrows Heritage conducted a community excavation of the Broch. Originally it was thought to have been a single walled broch, however a central staircase was found and some internal cells. Click on the links below for full reports on the excavation.