The surf reef is predicted to bring £11m into Bournemouth every year
The cost of a development project in Dorset, which includes Europe's first artificial surf reef, has increased by nearly £2m.
Boscombe Village Spa Project in Bournemouth is now estimated to cost more than £11m, including £3m for the reef - double the first £1.4m estimate.
Additional costs including extra sand for the reef and delays caused by bad weather have been blamed.
The project, originally due to open last month, will now open in September.
The decision by Bournemouth Borough Council to approve an extra £1.81m is expected next Wednesday just seven months after councillors assigned an extra £974,000 to the project.
The council predicts that anticipated income from the scheme will balance the additional costs, funded from the council's capital programme pot.
Roger Brown, Bournemouth council's service director for leisure, said part of the cost increase included a £100,000 council contribution to stopping and restarting the project over winter.
"[Also] we've brought into the equation the cost for refitting the surf pods, that will be fully met by the sales of the units," he said.
"We have to get a new licence from government to construct the reef as it was time limited and ran out in September."
The reef, which will consist of 55 sand-filled bags, is 225m (740ft) out to sea, east of Boscombe Pier and covers the size of a football pitch.
It will be one of four artificial reefs worldwide, including Narrowneck, Queensland, Cables, Western Australia and Mount Maunganui, New Zealand.
Work on the scheme is due to resume in April.