US operator Tauck plans to resume all remaining 2021 itineraries during August and September.
The move follows confirmation of the restart of selected tours and cruises in recent weeks.
Tauck expects to operate more than 80% of its pre-pandemic programme of tours and cruises this year, with a full return of all itineraries due in 2022.
The resumption plans includes Danube and Rhine river cruises, land tours in Italy and across Europe, plus trips to destinations ranging from Morocco to Machu Picchu.
Chief executive Dan Mahar said: “We are absolutely thrilled to announce the global restart of our 2021 journeys.
“If a destination is welcoming American travellers, and if it’s a place where Tauck operates, we’ll be bringing our guests there in the coming months.”
He added: “The challenges of the past 15 months have been unprecedented in our 96-year history but the loyalty of our guests and travel advisors, the skill, dedication and hard work of our employees, and our bedrock philosophy to always ‘do the right thing’ have brought us to this day.
But Mahar also sounded a note of caution: “To date the world’s return to travel has gone very, very well, and we have great cause for optimism.
“However, some restrictions remain in place for destinations like the UK and Canada, and we know that as our industry recovers, there will be twists and turns along the way.
“We’re as prepared as possible, but we know that the best attitude is to expect the unexpected and to stay flexible.”
Tauck has begun operating an increasing number of tours and cruise departures in the US and elsewhere.
The company recently announced the August resumption of selected land tours and cruises in Europe, cruises in the Galapagos Islands and safaris in eastern and southern Africa.