A £10m hotel and adventure centre at Surf Snowdonia has been given the green light by Conwy councillors.
The development at Dolgarrog promises to create 145 full and part-time jobs at the former aluminium works site.
Planning officers had recommended refusal amid concern about its impact on a rural area and flood risk.
But that was changed ahead of Wednesday's planning meeting after the council received updates from the applicant.
Speaking against the plans, Catherine Mortimer Hart, of Conwy Valley Civic Society, said: "Surf Snowdonia is a massive development in the county and has been a good use of a redundant industrial site, with the activity to date being enjoyed by thousands of visitors.
"The original application promised a major boost to all tourism businesses in the area.
"However, this proposal threatens to make the site completely self-contained and this will diminish the opportunities for local enterprise."
Snowdonia National Park and the Campaign for the Protection for Rural Wales also raised objections to the scheme, claiming it was too big for the area.
Andrew Ainscough, of Surf Snowdonia, said it had attracted more than 600,000 visitors to the artificial surf lagoon since opening four years ago, employing 140 full and part time staff at peak times.
He said the new development would complement the surfing business, making it a year-round attraction, and that any issues raised by officers could be addressed.
"Phase two will also enable us to make phase one jobs less seasonal and more robust," he said.
"The benefit of this to the local economy cannot be underestimated."
Louise Emery, Conwy's cabinet member for economic development, backed what she called an "exciting and ambitious development", saying it supported the council's push for year-round tourism and an improved night-time economy.
"This scheme would deliver both," she said."