Gray Line will be offering direct bus service between Akureyri and Keflavík Airport as of next spring, according to mbl.is. There will be three rides a week—Tuesdays, Thursdays and Sundays—in April and May, but daily between June 1 and mid-September. Departure from Keflavík will be at 5:00 pm, arrival in Akureyri around 11:00 pm. From there, the bus will depart at 11:15 pm and arrive in Keflavík at 5:15 am. Thus, passengers arriving in the afternoon will make it to Akureyri before midnight, and those coming from Akureyri will arrive in Keflavík early enough for a morning flight.
Stops will be made in Borgarnes, Staðarskáli, Blönduós and Varmahlíð. A one-way fair to Akureyri will be ISK 11,000 (USD 86, EUR 76), but less if you get off at one of the stops.
The service will begin Sunday, April 3, 2016.