The whole of Thomson will be transitioning, including resort staff, while the Sensimar and Family Life brands will be seen alongside Tui.
The Tui Discovery will be the first of the fleet to offer an all-inclusive drinks package as standard.
“Tui is a recognised and trusted brand in other countries and we want customers in the UK to get to know and love it too as we transition from Thomson to TUI," Nick Longman, managing director of Tui UK & Ireland said.
"Investment in our product to enhance and personalise the customer experience is fundamental to the ethos of the TUI brand and what better way to demonstrate this than unveiling our newest addition as Tui Discovery and introducing all-inclusive as standard.
"The introduction of Tui Discovery marks a new era for our cruise business in the UK which will continue with the introduction of two more Tui ships to the fleet over the next three years."
Tui Discovery and Thomson Majesty will both be based in Palma during summer 2017 with Thomson Dream based in Corfu. Meanwhile, Thomson Spirit will sail from Dubrovnik.
Thomson Celebration, will spend its summer between Malaga, Spain in May and October and ex UK sailings from Newcastle between June and September.
The new bases will lead to 12 new itineraries, more choice in the Mediterranean and a larger range of durations.
Helen Caron, managing director of Thomson Cruises said: "The line-up for summer 2017 is set to be our most exciting programme yet with some incredible new itineraries and ports of call.
"From the culture of cities likes Casablanca and Copenhagen to the culinary delights of the Tuscan Riviera and the spectacular scenery in Croatia and the Norwegian Fjords we have something to offer families and couples alike.
"All this, alongside tips and service charges included and flights from 22 airports across the UK. We’re confident that our customers will love everything that summer 2017 has in store."