It is easiest to approach Eldborg from Snorrastadir farm on its southern side, walking on a marked hiking path 2,5 km through the shrub-covered lava field. It is possible to walk all the way around the crater as well as to the top of the crater. The walk takes an hour or so.
It is a magnificent site, not just for those interested in the geography or volcanologists. It definitely makes for a great photograph, with the great Snaefellsjokull glacier in the background.
Eldborg crater is about two hours drive from Reykjavik.
Check out our complete guide to Snaefellsnes peninsula.