Work on the interior of the terminal has included the installation of a new security search area which is reducing average queuing times to six minutes.
The World Duty Free area has also had a refit that as part of an overhaul of the retail area which has seen it grow by 30%.
Belfast City Airport chief executive Brian Ambrose said: "We’re delighted to see the finished terminal facilities and I am confident that those travelling through Belfast City Airport will be impressed.
“Speeding the passenger journey through security search, whilst maintaining the integrity of the process, is of the utmost importance.
“Using the very latest equipment and technology, such as automatic tray return facilities, e-gates and additional lanes, customers can now expect an average processing time of 6 minutes.
“In addition to the improvements inside the terminal, the airport’s car park booking system has been upgraded, and a ‘Premier’ car park introduced.
"We have also welcomed the first of three new fire tenders which are equipped with the very latest fire and rescue technologies."
He added further work will see a covered walkway to the car park built in 2019.