The 60-year-old line was part of All Leisure Group, which collapsed last month.
In a statement G Adventures said acquiring Swan Hellenic “further diversified G Adventures’ portfolio of brands, adding boutique small ship cruising to its existing adventure travel, adventure cruising, and new touring businesses.”
The move follows the operator’s recent purchase of established pioneering British escorting touring names Travelsphere and Just You.
John Warner, vice president of global sales, G Adventures, said the company was “determined the legacy of this great UK brand would live on”.
“We know how beloved Swan Hellenic is to its loyal customer base and respect it has in the British travel community. Our long-term aim is to re-launch Swan Hellenic and re-establish the award-winning values that make it so well-loved," he added.
G Adventures plans to restart the operation of Swan Hellenic in 2018. The operator said itineraries would be announced this summer.