BT has set about connecting the Scotland's Northern Isles to its 21st Century Network (21CN).
A new 70 kilometre fibre optic submarine cable will be laid from Skaill Bay in Orkney under the Pentland Firth to Dunnet Bay, near Thurso.
An independent marine engineering company has been brought in to carry out the works, which will provide a broadband connection to the Northern Isles alongside existing microwave radio links.
BT Scotland's director, Brendan Dick, said: "This is another major step forward in the massive amount of preparatory work we are progressing so that people living in the Northern Isles can share in the benefits that our next-generation network will bring.
"It's one of the biggest projects BT has ever undertaken and much more work will have to be done before 21CN comes to Orkney and Shetland."
Almost 60 exchanges on the islands will be replaced with 21CN equipment, part of a programme affecting 1,000 exchanges across Scotland.