The airline has confirmed its last flight will be October 27 and had taken the decision due to lack of demand.
It operates flights to Boston and New York from the airport.
The budget airline announced routes from Belfast International to the US in February 2017, with flights beginning in July last year from as low as £69 a ticket.
The Dublin services will remain.
A Norwegian spokesperson said: “Following a comprehensive review of our services from Belfast in response to customer demand, we have decided to withdraw our routes from Belfast to the New York and Boston areas.
“Customers can still book flights between Belfast and the US on our website for travel up to 27 October 2018.
“New York and Boston-Providence remain well served by Norwegian from Dublin, Shannon and Cork with up to 33 weekly departures, giving customers in Northern Ireland an alternative for booking daily affordable flights to the US.”
Prior to Norwegian launching its routes from Belfast, United Airlines ran Northern Ireland’s only direct link to the US for years before poor financial performance rendered it unsustainable.
A £9million rescue deal agreed by Stormont and United collapsed a few months before the route was halted because the financial package breached EU state rules.
The route between Belfast International Airport and Newark Airport first began in 2005, operated by Continental Airlines.
United took over the operation of the route in 2012 following a merger between the airline and Continental.