Tresco and Bryher have had no superfast broadband since Friday morning following last week's storms.
The two islands receive their superfast service from a cable that runs from St Mary’s to Tresco and on to Bryher. However, high winds washed away part of Tresco's shore, taking some 172m of duct line and the cable with it.
The Isles of Scilly's Openreach engineer Stuart Moore and colleagues from the mainland managed to locate the fault, which began at around 5am on Friday.
He told This is Scilly: “The guys brought some testing kit over that could tell how far away the fault is, then it’s just a matter of walking the route.
"Tresco’s IT manager Tony Redding and I were doing that and then some of the route just wasn’t there. It had washed away.”
He said that a temporary service will hopefully be in place tomorrow (Tuesday) until engineers can "dig in all the replacement duct", which could take several weeks.
He went on to praise Tresco Estate for being “very, very helpful and understanding”, adding: “It was an act of God, just a result of the storms we had on Friday. But everything is done online these days, no business wants to be without its superfast broadband.
“It’s just fortunate it happened now rather than the middle of the season."