WOW Air is set to fly to California from summer 2016, with two new routes to LA and San Francisco confirmed.
The Icelandic carrier already flies direct from Dublin to Reykjavik, which means Irish passengers will be able to connect to the West Coast cities with an estimated total journey time of 13.5 hours.
Prices will not be confirmed until flights go on sale in January 2016, the airline has told Independent Travel, but lead-in rates are likely to be considerably lower than the €329 each-way fares quoted for direct flights from Dublin to LA by Aer Lingus.
Aer Lingus is to fly direct to LA from May 2016, while Ethiopian Airlines has been operating a direct service from Dublin Airport since June.
WOW's stopover time in Reyjkavik is likely to be two hours, the airline says, and the Reykjavik-US route will be serviced by three new Airbus A330-300s aircraft, the first wide-body planes in its fleet.
Low-cost transatlantic travel is gathering momentum as fuel prices drop and the economy recovers, with Norwegian set to fly direct from Cork Airport to Boston from next May using narrow-bodied Boeing 737-800s.
WOW's "ultra-low-cost" transatlantic services also connect Dublin, via Reykjavik, to Boston and Washington, with its lead-in fares gaining wide publicity.
Flights from Dublin to Boston are currently quoting from €149 each-way on its website (wowair.ie), for instance, though they rise to as much as €454 on certain dates, excluding baggage fees.
By contrast, as we publish, Ethiopian Airlines' website (ethiopianairlines.com) is quoting return fares to Los Angeles from €449 next May.
WOW Air allows one cabin bag of less than 5kg for free, while charging €15 each-way for cabin bags of 5-12kg and €31 for checked bags of up to 20kg.
WOW's capacity will more than double to 1.8 million next year, it says.