The average cost of a house on the idyllic island off the coast of Argyll is £73,539, compared with £672,874 in the most expensive seaside town of Salcombe, Devon, according to the survey of house prices in 196 locations across the country carried out by Halifax.
Other Scottish seaside retreats dominate the top ten on the “most affordable” list, including Campbeltown, Thurso, Girvan, Wick, Saltcoats, Stranraer and Irvine. .
Isle of Bute councillor Isobel Strong said it was a bargain: “The whole of Bute, including Port Bannatyne, is such a lovely place to live. I moved here 40 years ago and have never left.
“We have the most gorgeous scenery, great attractions and lovely places to eat and drink.
“Not only that, we are a 35-minute ferry trip to the mainland, and a 90-minute commute to Glasgow, which is ideal for people working in the city.
“We have a population of 7,000, with about 1,000 in Port Bannatyne and 4-5,000 in Rothesay.
“There are some people who have second homes here, but really when people come here they just want to stay.
“The island has everything for everyone, including walking, rambling, sailing, kayaking and birdwatching.
“It would be nice to attract more younger people to the island and there are still quite a lot of properties available for sale here.
“Once they come then hopefully they won’t want to leave again.”
Bute is one of the most accessible Scottish islands with a short ferry ride across the Firth of Clyde, and is renowned for its glorious gardens and grand architecture.
The Halifax survey found that, over the last 10 years, the average house price in a seaside town has increased by almost one third to £208,729.
The increase means seaside homes have added around £410 a month to their value over the last decade.
The biggest increases in the average price of homes in seaside towns over the past decade were all recorded north of the Border.
Fraserburgh in Aberdeenshire recorded the largest rise, with a 109 per cent increase in property values to £132,920 in 2015.
Lerwick in Shetland and Peterhead in Aberdeenshire experienced the next largest rises, both recording a 102 per cent upswing.
Halifax said that outside southern England, the most expensive seaside towns are also in Scotland. The average house price in St Andrews is £294,586, while the typical home in North Berwick costs £294,076 and the average property value in Stonehaven is £243,741.
Craig McKinlay, mortgages director at Halifax, said: “Seaside towns have a distinct attraction, offering that all important sea view with a typically high quality of life in a healthy environment.
“There is a romance associated with living by the sea and this is evident in the high house prices seen in many of these areas.Some of the most expensive seaside towns in Britain are dotted along the southern England coastline while many of the least expensive are in the north, particularly in Scotland.
“Despite a clear north-south divide in property prices among seaside towns, the rapid price growth in many Scottish seaside towns over the last 10 years suggests the popularity of coastal living has spread out across the whole country.
“Of course, the boom in the Scottish oil sector during the period also provided a boost to house prices, particularly in several towns along the Aberdeenshire coastline.”
Nitesh Patel, housing economist at Bank of Scotland, added: “Seaside towns are highly popular places to live in Scotland as they offer a unique lifestyle.
“A number of seaside towns have recorded substantial house price increases over the past decade, predominately on the east coast.
“Scottish seaside town house prices have done particularly well over the last 10 years, outperforming the average for Great Britain as a whole.”
The research used house price figures from the Land Registry and the Registers of Scotland.