Expansion of its Edinburgh service means that Monday flights will increase from 3 to 4; and those on Tuesday and Wednesday from 2 to 3.
There will be 3 flights to Manchester on Monday, Thursday and Friday – up from the current 2 daily flights.
And on easyJet’s 4 London destinations (Gatwick, Luton, Southend and Stansted) there will be extra flights on weekday mornings and evenings, particularly aimed at business travellers.
All the changes will be effective from the start of easyJet’s winter schedule on 28 October.
Earlier, on 22 October, the airline will launch its first service from Belfast International Airport to Birmingham.
Flights for all routes are now on sale at www.easyJet.com with fares from £24.99, one way including taxes.
Ali Gayward, easyJet’s commercial manager, said:
“Our aim has always been to make travel easy and affordable, and we remain committed to Northern Ireland. We are adding these extra flights in response to increasing customer demand for easyJet services.
“Edinburgh and Manchester are important centres for the business community and also for leisure travellers, including people going there for our popular city breaks.
easyJet’s recently-launched fourth route to London – London Southend – has already proved extremely popular, with a direct train link taking passengers to Liverpool Street station and the City of London in under 55 minutes.
Uel Hoey, business development director at Belfast International Airport, said:
“We very much appreciate easyJet’s long-established commitment to developing its service and providing stability for millions of Northern Ireland air travellers over the years.
“We are delighted that the airline is again demonstrating a willingness to explore new horizons in support of Northern Ireland’s economic growth.”
Ali Gayward added: “There has been a warm welcome for our new Flexi fares, which give passengers unlimited flexibility to change the date of their flights up to two hours before the scheduled departure time. We are also trialing allocated seating.
“All round, we are grateful to the Northern Ireland public for their support and we will continue to strive to provide them with the best possible service.”