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Reykjavík Domestic Airport is based just south of Tjörnin on a wide stretch of fenced-in land. From morning to evening, planes fly between Reykjavík and Akureyri, Egilsstaðir and Ísafjörður; as well as to Greenland and the Faeroes. Internal flight operator Air Iceland has a desk at the airport, but you can usually save money if you book over the internet (a computer terminal is provided near the check-in desks). Eagle Air also operates sightseeing services from here.
The journey from Keflavík International Airport to Reykjavík takes about 50 minutes. Taxis cost around kr15,000. Three easy bus services connect Reykjavík and the airport and are by far the best bet; kids get discounted fares. From the Reykjavík Domestic Airport it’s a 1km walk into town, there’s a taxi rank, or bus 15 stops near the Air Iceland terminal and bus 19 stops near the Eagle Air terminal. Both go to the centre and Hlemmur bus station.
Flybus Operated by Reykjavík Excursions, Flybus meets all international flights. One-way tickets cost kr1950. Pay kr2500 for hotel pickup/drop-off (which shuttles you from/to the Flybus at the BSÍ terminal); you must book this a day ahead. A separate service runs to the Blue Lagoon (from where you can continue to the centre or the airport; kr3600). Tickets online, at many hotels, or at the airport booth.
The Flybus will also drop-off/pickup in Garðabær and Hafnarfjörður, just south of Reykjavík.
K-Express At the time of writing K-Express offered three daily buses between Keflavík International Airport and Keflavík Town, Reykjavík Campsite, Hallgrímskirkja and the Harpa concert hall for kr1300. They depart (and have a desk) about 500m from the terminal, at the building with the Sixt rental car agency. Get tickets from the bus driver or online.
Airport Express Operated by Gray Line Tours between Keflavík International Airport and Lækjartorg Sq in central Reykjavík (kr1900), or via hotel pickup/drop-off (kr2400). See website for schedule.