The 32m-high, six-storey tower replaces the old two-storey structure that was built in the 1960s.
Airport bosses say the new tower has been equipped with the latest state-of-the-art technology and provides air traffic controllers with much better views of the runway.
Southend’s air traffic control team have spent several months undertaking familiarisation and essential training in the new building.
The airport’s managing director, Alastair Welch, said: “The completion of the new control tower is another successful step forward in Stobart Air’s investment and development programme to enhance the airport – along with the new terminal, train station and forthcoming hotel.
“It will not be long now before we are providing a whole range of opportunities for local people to fly to a range of holiday and business destinations across Europe.”
The airport’s £12million train station is expected to open in the next month or so, while the new £10million terminal building, opposite the station, will open in October.