Loch Fad is a freshwater loch on the Isle of Bute in Scotland.
Its name means "long loch" in Scottish Gaelic. It lies on the Highland Boundary Fault.
Its surface area is 71 hectares, fairly large for a freshwater loch on an island in Scotland.
It is the site of one of the largest rainbow trout cage farms in the UK.
In 2018, it was used for tests of Donald Campbell's boat, Bluebird.
