Two of its hotels also came home successful from the World Luxury Spa Awards on Saturday (July 14), with Thorpe Park Hotel & Spa in Leeds winning best Luxury Fitness Spa in the UK and Cottons Hotel & Spa in Knutsford scooping the title for top Luxury Hotel Spa in the UK.
The annual awards ceremony rewards and celebrates spas that set benchmarks in quality, innovation and service.
Thwaites Hotels Operations Director Chris Hill said: "We are thrilled with this news. The last 2 years has seen significant investment in our spas and there is more to come, as we are updating everything from the pool halls and gyms to the changing rooms and relaxation lounges.
"It's a really exciting time for us and to win these awards highlights how our plans are creating something quite special.
"I'm so proud and delighted for our spa teams who work so hard to ensure everyone who visits us has a fantastic time and enjoys some quality relaxation."
Over £1.5m has been pumped into Thwaites' six spas over the past two years.
This includes a complete refurbishment of pool halls at Kettering Park and Cottons, an upgrade of changing facilities at Solent Hotel, Fareham, and Aztec in Bristol, improvements to the treatment rooms along with the introduction of a manicure/pedicure station at Thorpe Park, and the launch of a new generation of gyms at North Lakes in Penrith.
This month the spas launch a new partnership with Caudelie which is already creating a buzz among its members, and there is another £1m of investment planned across the 6 sites over the next 2 years.
Chris Hill added: "This is the largest period of investment we have had in our spas - we have a stunning design plan for each spa and gym, we are improving every aspect of the guest experience and are looking at how we can add more to each person's visit, including incorporating new technology into facilities.
"Feedback so far has been fantastic - as we are now seeing from these awards we have won - and there is even more planned for the future. It's the ideal time for people to come along, see what we are doing and enjoy a bit of pampering."
For more information visit http:www.spa-and-fitness.co.uk.