Thornton transitions up from his role as managing director of the adventure tour operator which he has been in for the last three years.
His promotion comes as Intrepid revealed that the UK had grown by 67% over the last year and overtaken Australia as its number one outbound market for the first time.
Thornton takes over from co-founder Darrell Wade, who has been made executive chair.
Thornton, 35, becomes Intrepid’s first non-founding chief executive and said he aims to grow the Group’s sustainable tourism offering and further develop its small ship adventure cruise product.
His appointment comes on the back of strong global results for Intrepid which saw 20% growth during 2016 and a 37% year-on-year increase in January.
It also marks 20 months since Intrepid, whose brands include Intrepid Travel, Geckos Adventures, Peregrine Adventures, and Urban Adventures, split from its partnership with Tui.
The Group also features 19 destination management companies and the not-for-profit The Intrepid Foundation.
Intrepid recently announced plans to boost its relationship with the UK travel trade through its Intrepid Loves Agents incentive programme and its intentions to double its number of fam trips this year from three to six.
Thornton’s rise to chief executive comes as a result of 12 years spent with the operator where he started as UK sales and marketing coordinator before moving to Australia ten years ago and serving as managing director for the last three.
Thornton said: “Darrell and Manch [fellow co-founder Geoff Manchester] started Intrepid 28 years ago with the simple idea that travel could change the way people see the world. Their original vision has never been more important.
“It’s a privilege to be able to lead Intrepid into the future. We have a responsibility to support the communities in the destinations where we operate. I believe that business can be a force for good and now that we have a sustainable business model, we’ll be even more actively pursuing our growth with purpose.”
Darrell Wade added: “The growth that James has helped the business to achieve over the past 20 months reassured us that we have a sustainable future ahead – that purpose beyond profit can be profitable.”