The island has a long history having been home to Norse travellers and is now currently home to a Royal Air Force radar station and the SaxaVord space port.
The new network has been built by Openreach and sees signal travel from the head end exchange at Sullom Voe and crosses two subsea cables before reaching the island.
Business Minister Richard Lochhead said: “Connecting the island community of Unst is a remarkable achievement and a clear demonstration of our commitment to delivering faster broadband to communities across Scotland through the Scottish Government’s R100 programme.
“Access to reliable, high-speed internet is transforming lives and livelihoods across the country. It empowers small businesses, enables remote working and helps attract new investment. We remain committed to working with Openreach to expand the reach of our investment in faster, more dependable broadband – ensuring that public funding delivers tangible benefits for communities in every part of the country.”
Robert Thorburn, Openreach Partnership Director for Scotland, said: “We’re committed to making sure the most rural parts of Scotland have access to fast and reliable broadband – and this is just another example.
“Our extensive network means residents can shop around and find the best deals that suit their needs. But it’s important to remember that upgrades don’t happen automatically. People need to order it to take advantage of the technology.”