A BEACHFRONT island property in Gladstone's Harbour is for sale, and the price tag won't break your bank.

A 1500 sqm block at Lot 5 Quoin Island is on the market for $35,000.

One Agency director Tanya Williams said Quoin Island properties were "tightly held".

The block is the second property on the island Ms Williams has sold during her seven years as a real estate agent in Gladstone.

She said the Mooloolaba owners did not use the block often, preferring to stay on their yacht and sail during holidays.

Judging by the inquiries made so far Ms Williams expects the buyer to be based in the Gladstone region.

"It's a lovely location over there and it's quite close and handy to Gladstone," she said.

"You'd have to go through council approval (to build) but you could start with a shed with some solar power and a water tank ... then you could build a home.

"It's a great opportunity for someone who wants to buy on an island and it's not going to break the bank."