From early March, signs will warn of a 50mph zone covering less than one mile from Sandwater towards the South Nesting junction, due to new road junctions coming into use.
In the coming weeks, a section to the north of the Lang Kames, south of Voe, will also be subject to a new speed limit, where new wind farm access tracks will extend from either side of the main road.
The signs will be accompanied by flashing displays showing the actual speed of oncoming cars and a warning message if they need to slow down.
The costs of the signs and works are being paid by the main wind farm contractor RJ McLeod.
The speed limits are expected to remain in place for the duration of the wind farm construction phase, which is expected to end in late 2024.
The changes have been authorised by Shetland Islands Council as the road authority.