Adventure Parc Snowdonia's Hilton Garden Inn hotel and Wave Garden Spa have entered the final build phase ahead of opening next year.
Practical completion for the £11m project is on track for January 2021 with a planned opening date of 26 March 2021.
The 106-bedroom hotel will include Zephyr's Restaurant & Bar on the ground floor, while the Wave Garden Spa will feature indoor and outdoor treatment areas, vitality pools, a yoga studio, hammam and Himalayan salt sauna.
After a year with no visitors at all – Adventure Parc Snowdonia took the decision not to open during the pandemic – the brand suggested 2021 could be its busiest yet, with booking data "pointing towards unprecedented demand for UK staycations".
Adventure Parc Snowdonia managing director Andy Ainscough said: "We've been heartened by the demand for longer breaks, with many more guests than we anticipated checking in for seven and 10-day holidays. People are excited by the idea of staying in our adventure hub, as much for our on-site adventures and spa facilities as our proximity to the big landscapes of the Snowdonia National Park.
"We're beginning to see some real optimism return to our sector and that's great. I have no doubt North Wales tourism can make a robust recovery, and whatever happens next year, it will come back even stronger than before."
Jim Jones, chief executive of North Wales Tourism, said: "At North Wales Tourism we are extremely excited by one of the most renowned hotel brands becoming part of our dynamic regional tourism destination. It will come at the perfect time to give our £3.6b tourism economy a real boost as we restart after a miserable 2020."
Adventure Parc Snowdonia launched its world-first inland surf lagoon, Surf Snowdonia, in 2015, followed by an indoor adventure hub last year.