The ultrafast fibre will be laid by Openreach to serve properties in Altnaharra and Skerray, near Bettyhill, in Sutherland.
Forty-five households linked to the Altnaharra telephone exchange are to benefit, Openreach said.
One hundred premises are involved in the upgrade in Skerray.
Workers from Altnaharra Estate will dig in the new cable on the estate, while people in Skerray with the relevant skill and experience are carrying out the digging to specifications agreed with Openreach.
People living in small Highland communities are excavating the trenches needed for cables to boost their broadband connections.