Travelsphere and Just You have become the latest operators to join the Association of Touring and Adventure Suppliers (Atas).
The association, which was launched last week, aims to incentivise travel agents to increase knowledge and sales within the sector, with a series of promotions and rewards due to be unveiled in the coming months.
Just You and Travelsphere join 21 other leading touring and adventure travel suppliers already signed up.
The brands were acquired by G Adventures in January from administrator Grant Thornton following the collapse of All Leisure.
Atas will have a presence online and in print through the Travel Weekly portfolio, and will hold an overnight agent conference in the autumn.
Giles Hawke, chief executive of Cosmos Tours & Cruises, was appointed chairman for the association’s first 12 months.
Other members include G Adventures, Intrepid, Titan, Trafalgar and Wendy Wu Tours.
Sales director Colin Wilson said: “We are excited about the prospect of growing the sector through the trade and our two leading brands will give agents yet more choice.
“Atas is the perfect vehicle and will complement our other planned trade activity.”