The revolutionary technology will allow wind power to be harvested in waters too deep for the current conventional bottom-standing turbines.
The Peterhead wind farm, known as Hywind, is a trial which will bring power to 20,000 homes.
Manufacturer Statoil says output from the turbines is expected to equal or surpass generation from current ones.
It hopes to cash in on a boom in the technology, especially in Japan and the west coast of the US, where waters are deep.
"This is a tech development project to ensure it's working in open sea conditions. It's a game-changer for floating wind power and we are sure it will help bring costs down," said Leif Delp, project director for Hywind.
So far, one giant turbine has already been moved into place, while four more wait in readiness in a Norwegian fjord.
By the end of the month they'll all have been towed to 15 miles (25km) off Peterhead, Aberdeenshire, where they'll float upright like giant fishing floats.
While the turbines are currently very expensive to make, Statoil believes that in the future it will be able to dramatically reduce costs in the same way that manufacturers already have for conventional offshore turbines.
"I think eventually we will see floating wind farms compete without subsidy - but to do that we need to get building at scale," said Mr Delp.