Crossing the Arctic Circle was on my bucket list - so my wife arranged a trip to Grimsey as part of our Iceland voyage

The experience is nothing... read more short of amazing. Hella picked us up from the airport and took us to her cozy guesthouse. The place is very clean and she provided tasty continental breakfast, snacks and coffee throughout our stay.
Hella perfectly planned our time (we had about day and a half): we went to the cirlce marker right away (you can not drive right up to it, so budget for some walking) - and then offered us few hikes to choose to see other things island has to offer - and that is. of course, puffins! You can see them pretty much everywhere but Hella and her friend pointed out the best photo spots. There is literally no question about Grimsey she could not answer.
The most important part, however, is Grimsey is very small - less than 50 permanet residents - so having a local host makes a huge difference! Hella knows everybody on the island - so for our short stay we really felt like part of the community.
From learning the history of every building, to making reservation at the island's only restaurant (don't miss it!) to knowing the hours of the convenience store - local host is a must.
Our 5 year old really enjoyed the experience too - and established an instant bond with Hella and her friend.

Few random suggestions:
- we flew to the island and took the ferry back - this is a good combo - the views on the flight are amazing and you get to spend more time.
- spend a night there - not only to hedge your bets with weather - but it also gives you chance to truly enjoy midnight sun and sample local restaurant
- if you have time in the evening - visit island pool - there is something surreal about swimming in a real indoor pool on an island with a population of less than 100
- Hella is setting up a scuba diving operation - see puffins underwater. Be prepared to wear dry suit.

Well... I am already looking forward to going back to Grimsey