I am conteplating travelling from SFO (San Francisco, USA) to HEL (Helsinki, Findland) via Reykjavik. Besides de price, the trip is attractive because it has a 20 hour layover in Reykjavik, from 10:30am to (next day) 6:30am.
Is it possible to leave Reykjavik airport during a long layover?
If so, would you recommend a specific plan to visit the city or even some attraction outside the city?
[According to the Iceland government I don't need a visa to enter Iceland and I have a US Greencard.]
Assuming that they layover is actually in Keflavik airport (which it almost certainly is; Reykjavik itself just has domestic flights, and a few connections to neighboring locations in the North Atlantic):
Yes, you can leave the airport during your layover. Since your destination is Finland, and both of Iceland and Finland are in the Schengen area, you'd be passing through immigration controls in Keflavik anyway, and then nothing stops you from leaving the terminal until your Schengen-internal flight to Helsinki departs.
Beware when putting your plan together, that Keflavik is quite a distance away from Reykjavik. It's about an hour's drive, and public transport options are limited to airport buses. Research in advance to find a bus departure that will get you to the airport in time to make it through security for your early-morning flight.
(This question looks relevant).
