Glacier Journey offers snowmobile and super-Jeep tours, plus winter ice-cave exploring. In summer (June to September) it operates from a base at Flatey farm and accesses its snow course via Rte F985; in winter the base is at Jökulsárlón. Snowmobile tours cost 24,500/12,250kr per adult/child, with two people to a skidoo; solo riders pay an additional 10,000kr. There's midnight-sun offering in June and July.
If you prefer less exposure to the elements, a super-Jeep tour on the ice is 23,500/11,750kr.
Winter ice-cave tours (20,500/10,250kr) can be done from November to March; in good conditions, you can combine a tour with some snowmobiling.
For all tours, reservations are required.