This is a comment that always pops up regarding Harbour Island. There are a lot of reasons to explain the expensiveness of the Island.

1- The island is very small 3.5 miles by half a mile so that a first factor to take in account
2- it is known as the island of Billionaires, so it attracts the who’s who of our world, actors, artists and entrepreneurs. Real estate pricing is quite outrageous at par with the most expensive cities in the world. A ¼ acre land on the beach side can cost 5 to 6 Millions if available. A 4000 sq. ft. 40 years old house that needs intense renovation was just sold for $ 8 millions. A recent 10 000 sq. ft. house should fetch up to the mid $ 25 millions.
3- Bahamas has hefty import duty fees from food to basically everything
4- basically everything consumed in the Bahamas comes from the US so transportation costs is a significant added cost
5- Locals just wants to charge whatever someone is willing to pay, this explains why a massage costs the same in Miami as it does in Harbour island
6- The simple economic rule of offer and demand, Harbour island has a limited offering of everything. Plane tickets are expensive, hotels are expensive with around 200 rooms only for the whole island, vacation rentals are expensive, etc.
7- Salaries are less expensive than in the US but way more expensive than other developing countries.