Any full service hotel will be able to accommodate checkins
24/7, especially if you give them a heads up. Most hostels
don’t staff checkin all night, but may be able to work
something out if you ask in advance.
You’d just need to pay for the prior night if you want to be
able to check in at the crack of dawn vs the actual checkin
time in the afternoon. If you’re debating if that’s worth it,
it is imo. The time difference is obviously different, but
arriving into Iceland from the States at 4am and trying to be
a functioning human until our Airbnb was available at like
noon was genuinely miserable. I would have gladly paid extra
for somewhere that was available as soon as we arrived.