We did not take any from Tour IS. I'm sure they could arrange if you want one. We bought SIM cards from hotel. They aren't expensive. But you need an unlocked smartphone. They are also available in stores at the airport.

Breakfast was included in our bookings in April. But heard from coworkers who went in summer months didn't have. But I am not sure which company they used.

Sorry for the late reply. Very detailed eg where to turn etc. I look through the details, do my own list for places (rough guide) to go before the trip, at least I have a rough idea how Long it takes to reach (worst and best case). Iceland’s change is unpredictable so always check the Veður (weather) app

I found somewhere the average temp for June is 42 F Low and and 55 F High. In early July it seemed to average about 50 F during the day, dropping down to upper 30s/low 40s at night.

I think 5-7 days would be enough. I would go counter clockwise on the island and also see the Blue Lagoon in Rejkavik (sp). .We used Tour.Is. and liked them very much. We rented a car from them and they gave us everything we needed to see the sights. We chose the level 2 hotels. They were not fancy, but certainly nice enough. All were very clean. Food is VERY expensive in Iceland. We ended up buying lunch meat, bread and fruit for our lunches. Breakfasts were included at all hotels. We also brought snacks with us for the long drives. We went in June. It was cold but manageable with coats, gloves and hats. Have a wonderful time.

Great question. We did the 7 day circle tour last summer. We added most of the optional activities and felt that we didn't have enough time to get to the activities AND drive the distances between each hotel. If I did this tour again, I would add a day after the glacier walk and after the whale watching. We did the glacier walk and then drove directly to the glacial lagoon and they were already closed when we arrived! We spent less than an hour at Lake Myvatn nature baths and still arrived at our nightly lodging after they had closed the desk for the night. We had to call our hotels everyday and tell them that we would be checking in after 8 or 9. This wasn't usually a problem with the bed and breakfast because it was summer. If you are traveling during a different season it would be more of a problem. We often walked into the restaurants right before they closed for the night. One night we got to our Bed and Breakfast too late to enjoy dinner in the one restaurant in town. We didn't usually eat lunch, or if we did, we ate on the road. That being said, this was one of the best experiences. I just hated feeling like we were rushing everyday. If you don't purchase the additional activities, you should make good time. If you do add the optionals, maybe ask about additional days in the middle of your trip. I found Tour.Is was flexible in scheduling options.