The budget airline is offering ultra-low fares for the summer.

Dublin Ireland
Credit: Getty Images

Norwegian Air is celebrating St. Patrick’s Day with up to 20 percent off flights from the U.S. to Europe.

Travelers can book flights to Ireland, Scotland, London, Oslo, Stockholm, Copenhagen, and Bergen starting at $84.80 one-way. The sale ends March 19.

Flights are currently available from New York City, Boston, Fort Lauderdale, Orlando, Los Angeles, San Francisco, and Connecticut, and depart from July through October.

Travelers can book cheap flights to Ireland, Scotland, or Bergen from April 18 and October 28, or to London, Oslo, Stockholm, or Copenhagen from April 18 through June 16 and from September 4 through October 28.

The budget airline recently got approval from the Federal Aviation Administration to begin new routes from the U.S. to Ireland and Scotland, and to offer customers what an airline representative said will be Norwegian's cheapest fares to Europe to date.

Norwegian Air CEO Bjørn Kjos also hinted in an interview with Boeing earlier this year that Norwegian's $69 flights from the U.S. to Europe could be making a comeback as early as this June.

Customers should note that the airline charges additional fees for amenities like luggage, meals, and seat assignments, which are not included in the base fare.