Thomson's 600 shops have been renovated to display the Tui name and the company has been running a television advertising campaign to inform customers that "Thomson is changing to Tui".
Tui UK and Ireland managing director Nick Longman said he hopes the move will boost sales as the firm expands its range of holidays from traditional bucket and spade breaks.
In an interview with the Press Association, he said: "Thomson is a great heritage brand with rich nostalgia and that's fantastic, we've all had great Thomson holidays over the years, but it can also be a bit limiting.
"Holidays are changing, people want different things, not just seven and 14 (night) beach packages.
"They want to go for different durations, with different generations of their family, do city breaks, do tours, all those different types of holiday experiences.
"I think that it can be harder to change people's perception of a brand when you try to introduce a wider type of holiday.
"Tui is a much more contemporary brand and certainly the research we did said people are much more likely to consider going on those other types of holidays if they go with Tui."
The Thomson brand was established in 1965 by Canadian media baron Roy Thomson.
Mr Longman insisted that the firm would "still do the things we've done before", but also appeal to a broader range of customers.
He went on: "It's a great thing to be part of a truly global brand as Tui's leading travel business in the world.
"It brings us a wealth of expertise, it means that we can utilise the knowledge of all of the representatives we have serving our customers overseas, doing that as one group.
"I think we can provide better experiences, better service for our customers."
Tui marked the announcement by unveiling a prototype of an innovative system which matches customers' facial and emotional responses to images of destinations and experiences to calculate their perfect trip.
The firm claims the Destination U technology is a "world first in travel retail".
It hopes to make the system available for public use "in the near future".
Best beach holiday destinations for 2018
Best beach holiday destinations for 2018
If you're planning to head to the beach for your 2018 holiday, you'll want to know the best places to go for sun, sea and sand. We've picked the top beach destinations to visit in 2018, from the ones with the hottest new flight routes to the locations with the most exciting hotel openings.
Whether you're looking to stay in the UK, fly to the Med or travel to somewhere more exotic, you'll want to browse our 2018 beach holiday hit list...
One of the world's most desirable holiday destinations will be more accessible to British travellers when British Airways launches the only direct flights from the UK to the Seychelles in March 2018. Popular among honeymooners and luxury sun-seekers, the Seychelles offer some of the best beaches on the planet, lush mountain peaks and colourful coral reefs to explore. Book it: British Airways' twice-weekly flights from Heathrow to Mahé start from £699 return.
Aqaba, Jordan's resort city by the Red Sea, is undergoing a major tourism development, which will be completed in early 2018. Visitors will be able to experience a number of beach clubs, a new-look marina and dive a Hercules bomber sunk in late 2017, plus visit a new shopping mall and many restaurants. Five-star hotel Al Manara Saraya Aqaba – part of Starwood's Luxury Collection – and four-star Marina Plaza Hotel by Swiss-Belhotel are set to open before the end of 2018 and Hyatt is planning to open a hotel too. Book it: BA Holidays offers four-night holidays at five-star hotels from £681 per person, including flights and transfers.
A slightly poorer cousin of the glitzy Greek islands of Mykonos and Santorini, Corfu is set to receive a luxurious makeover in 2018 when two new glamorous hotels open. The first, Ikos Dassia, will open in May and offer dazzling views across the turquoise sea, sophisticated dining and elegant suites. New adults-only hotel MarBella Nido Suite Hotel & Villas opens its doors in May, bringing upscale romance, private villas and exceptional dining to the south-east corner of Corfu. Comedy series The Durrells will also return to screens for a third series, making the Mediterranean isle one of the hottest TV locations for a holiday in 2018. Book it: Sovereign offers seven-night all-inclusive holidays to Corfu, staying at the five-star Ikos Dassia, from £1,070 per person, including flights, transfers and airport lounge access.
The wind of change blows on the so-called 'Nature Island' of the Caribbean and visiting 'alternative' Dominica sooner rather than later will offer a more authentic beach experience. The first large-scale chain hotels, Cabrits Resort Kempinski and Tranquility Beach Resort Dominica (part of the Curio Collection by Hilton), are scheduled to debut in 2018, with construction starting on a third luxury development, the Silver Beach Resort & Spa. 2018 will also see the arrival of the first phase of the 'new' Jungle Bay Resort, destroyed by tropical storm Erika. It will relocate to a new site that will allow it to more than quadruple in size and go more upmarket. Book it: World Expeditions offers a 12-day Trek the Waitukubuli National Trail holiday from £2,490 per person.
Summer 2018 will see holidaymakers lust over Vis, when the remote and sleepy Croatian island takes a starring role as Greece in new Mamma Mia sequel, Mamma Mia, Here We Go Again. The original cast, which includes Meryl Streep, Julie Walters and Colin Firth, will reunite to continue their story. Vis is reached by catamaran from Split in under 90 minutes and offers a small island community feel, pretty fishing villages, coastal caves and smooth pebble beaches. Book it: Prestige Holidays offers seven-night escapes to the island, staying at the ten-room Hotel San Giorgio, with flights, ferry and transfers included, from £769 per person.
The Norfolk Coast Area of Outstanding Natural Beauty celebrates its 50th anniversary in 2018, when the LifeCycles and Landscapes project will place large-scale outdoor artistic and heritage works on sites along the ancient 400-mile Icknield Way from Dorset to the Norfolk Coast AONB, culminating with events at the Norfolk & Norwich Festival (11 to 27 May). 2018 will also see the third tranche of coastal access in Norfolk being opened within the Norfolk Coast AONB, from Weybourne to Hunstanton, making most of Norfolk’s coast accessible on foot. Book it: The Globe Inn at Wells-Next-the-Sea is a seven-room boutique hotel with rooms starting from £120 per night.
Known as the culinary capital of the Caribbean, Barbados promises authentic flavour and spice. 2018 will celebrate the culinary finesse of the island, with a great focus on quirky and wonderful food experiences like no other as new direct flight routes from Virgin Atlantic and Thomas Cook, plus new hotels, launch. Socialise with the locals on a Friday night or fish your own lobster and cook it up on a BBQ on the beach that evening. Visitors to Barbados can enjoy the best of Caribbean cuisine and rum, Bajan culture and festivals, along with dramatic stretches of crystal clear waters that frame coastlines of pristine sand. Book it: Virgin Atlantic's new service from London to Barbados launches in December 2017 and operates until April 2018, with fares from £1,213 per return.
The largest of the Canary Islands and a classic winter sun destination for UK travellers, Tenerife will become even more accessible in 2018 when British Airways launches its first direct route from Heathrow for winter 2017/18. The island will also host the launch of the respected Michelin Guide to Spain and Portugal in November and for families visiting Tenerife, animal paradise Loro Parque was recently awarded the best zoological park in the world in TripAdvisor’s 2017 Travellers’ Choice Awards. Book it: British Airways' new flights from Heathrow to Tenerife start at £98 return.
Australia’s playground for entertainment and adventure steps into the international spotlight for 2018 as teh Gold Coast hosts the Commonwealth Games. One of the host city's most exciting projects for the occasion is the Gold Coast Cultural precinct, catering for festivals, cinemas, concerts and events. Providing revellers a backdrop of surf, sand and sun, the Gold Coast is an up-and-coming hotspot for travellers with quirky bars and stylish restaurants popping up along the coastline. Book it: Austravel offers ten-night holidays to Queensland from £1,589 per person, including four-star accommodation, car hire and flights.
2018 marks 50 years since Mauritius proclaimed independence from the UK. The island's celebrations are set to include ceremonies, live music and performances on the national day, 12th March. As part of wider celebrations throughout the year, you can explore all four corners of the island - from the bustling and vibrant city of Port Louis in the north to the Chamarel Seven Coloured Earths and beautiful site of Le Morne Brabant in the south. The cultural and historical sites will really come to life during these celebrations and visitors will be able to see what a melting pot of cultures Mauritius really is. Book it: Hayes & Jarvis offers seven-night holidays to Mauritius from £1,318 per person, staying at the LUX* Belle Mare with airport transfers and return flights.