Eight new hi-tech check-in desks are the first of 30 that will be introduced this year to handle the growing number of passengers using the airport.
The desks form part of the first phase of works which also includes upgrades to the airfield, car parks and new upper deck seating areas to create more space for passengers in the departure lounge.
Paul Willis, London Stansted’s transformation director, said: “We’re delighted to reach this major milestone in our transformation programme.
"We’ve been working hard since the end of last year and it’s been fantastic to watch the project move away from the planning stage and come to life.
“Over the coming years, the whole landscape of the main terminal will change as we remodel the layout to a new ‘Shoreline’ check-in area which will stretch across the whole terminal.
"This will give passengers a more intuitive and easier journey through the airport and provide flexibility to allow us to accommodate new airlines as we grow as an airport."
He notes: “This is a really exciting time for London Stansted and its £600 million transformation programme.
"This investment will transform the experience for millions of passengers, unlock spare capacity and provide a greater choice of destinations and airlines. We’re confident passengers, airlines and staff will love the new Stansted when it’s fully completed in 2022.”
Phase 2 of the transformation project will see the construction of a £130 million arrivals building which is due to open in 2020.
The new terminal will be situated next to the current terminal and will include larger immigration and baggage reclaim areas, new retail facilities, improved access for all onward transport options and a public forecourt to create a welcoming environment for arriving passengers.
In Spring 2020, work will start to reconfigure the existing terminal building so that it is dedicated to departing passengers providing more space at check-in, security and in the departure lounge.
When the transformation is complete in 2022, Stansted will be the only UK airport operating dedicated arrivals and departures terminals.