The Lions will play their first Test for 12 years when they kick off against Tonga in Hamilton, New Zealand, on October 26.
They next face New Zealand a week later as part of a triple-header at Eden Park, Auckland which also includes Tests between Samoa and Fiji and Australia against Tonga.
Great Britain take on the Kiwis again in Christchurch on November 9 before leaving New Zealand and winding up their tour against Papua New Guinea at Port Moresby on Saturday, November 16.
The tour will be staged alongside a new Oceania Cup tournament involving New Zealand, Australia and Tonga in pool A and a pool B of Samoa, Fiji and Papua New Guinea.
The pool A winners will lift the Oceania Cup with the pool B champions receiving the Oceania Shield and promotion to the top group for 2020.
Rugby League International Federation chief executive Nigel Wood said: “International competition represents a wonderful opportunity for rugby league and this programme is both exciting and ground-breaking.
“It is uplifting that so much meaningful international competition is taking place around the globe in 2019 at all levels and it is also gratifying to see Great Britain Rugby League Lions reappear on the calendar, surely one of our sport’s most iconic brands.”