Vatnajokull (2110m) was named after sub-glacial lakes in a very volcanically active region in its centre. It is the largest glacier of Europe with an area of about 8,100 km², an average thickness of 400 m and the greatest thickness of about 1100 m. It contains approximately 3300 km³ of ice. The sub glacial landscape is an undulating plateau (600-1000m) with valleys and gorges. The icecap rises between 1400 and 1800 m above sea level. The ablation elevation is a bit different, 1100 m in the south, 1200 m in the west and 1300 m in the north. A great number of glacier snouts of different sizes flows down onto the lower lying areas. No glacier in the country has been researched more thoroughly than Vatnajökull. The research started in 1934, when the lake region erupted and ever since the Glaciological Society was founded in 1950 it has been continued every year.  The GS owns huts in several places on the icecap. The latest eruptions of the lake region took place in 1996 and 1998. The first confirmed trip across the icecap from the south and back was accomplished in 1875 by an Englishman and a few Icelanders. They were the first to see the Askja eruption the same year and report it to the people living on Lake Myvatn. The recreational company Glacier Jeeps - Ice & Adventure owns a hut (830m) at the edge of the glacier snout, Skalafellsjokull, and offers adventure tours on the icecap.

According to Guinness World Records, Vatnajökull is the object of the world's longest sight line, 550 km from Slaettaratindur, the highest mountain in the Faroe Islands. Guiness World Records state that "owing to the light bending effects of atmospheric refraction, Vatnajökull (2110m), Iceland, can sometimes be seen from the Faroe Islands, 340 miles (550km) away". This may be based on a claimed sighting by a British sailor in 1939. The validity of this record is analysed/undermined in mathematical and atmospheric detail by J.C. de Ferrant.

On June 7th 2008, the whole glacier and some of its surroundings, two existing Nationa Parks, and some nature reserves, were declared Europe's larges National Park, called Vatnajokull.

Hiking or cross country skiing on the icecaps depends entirely on the travellers themselves.  They decide where to go and are responsible for the preparations and the gear necessary for such endeavours.  Such trips or tours have to be reported to the police autorities on beforehand.