The works complete the first phase of an ongoing £15 million infrastructure investment programme.
The new, improved retail units now boast 552 square metres of retail space, which is an overall increase of just over 30%, in addition to an increased product range.
The gateway's commercial manager, Joanne Deighan, says: “Passengers will notice a huge improvement to the Departure Lounge.
The new World Duty Free and WH Smith units, which have opened just in time for our passengers flying off on their summer holidays, are bright and spacious with a much greater product offering.
“The walk-through design within World Duty Free allows our passengers to easily see the brands available as they move through the Departure Lounge and into WH Smith which overlooks the front of the airport.
“Over the summer months we expect to welcome approximately 10,000 passengers through the terminal each day so it’s fantastic to provide these customers with a world class travel retail experience that will really enhance the customer journey.
“Later this summer we will complete upgrade works to the security area allowing departing passengers to be processed much more efficiently and towards the end of the year passengers will be able to take advantage of an improved food and beverage offering.”
In addition to popular brands such as Benefit, Elizabeth Arden and Molton Brown, World Duty Free in Belfast City Airport will now for the first time stock a selection of Bare Minerals, Elemis and Smashbox products.
Ciara Hamill from World Duty Free in Belfast City Airport, said: “Seeing this project coming to life has been amazing and we’re excited to show off our fabulous new store to customers.
“The new walkthrough layout will revolutionise the World Duty Free experience for our passengers. The additional space makes for a much more relaxing, personal experience."
Upon completion towards the end of the year, the Departure Lounge will also feature additional seating space and charging points as well as improved toilet facilities.