Vidgelmir Lava Cave, Iceland - what to expect

Illustrative image - a scene in the spirit of the place, not a photograph of it. Real photos are below.

Vidgelmir is a lava tube in the Hallmundarhraun field, formed when the outside of a flow cooled into a shell while molten rock kept draining out from underneath. It runs for well over a kilometre and is one of the largest caves of its kind in Iceland by volume, with a collapsed entrance where daylight ends abruptly. Visits are guided only. A raised walkway and lighting have been installed along the accessible section, which protects the floor formations and makes the footing manageable, and helmets are issued at the start. Inside there are lava stalactites, colour bands in the walls and, from winter into spring, ice columns near the entrance.

What you actually see

The collapsed entrance - the daylight opening where the roof of the tube fell in.
The walkway - the raised metal path through the accessible section.
Lava formations - stalactites, benches and colour bands left as the flow drained.
Winter ice - columns and floor ice near the mouth from roughly January into spring.

When to go

Open all year with tours running daily, and winter and spring are the only times the ice formations near the entrance appear. Book ahead in summer, when slots sell out days in advance. The temperature inside stays a few degrees above freezing regardless of season, so bring a warm layer even in July.

Honest expectations

You cannot enter without a paid guide and the ticket is not cheap by any standard. Groups move together, so there is no lingering for photographs. The accessible section is a fraction of the cave's length. Anyone expecting to crawl through raw lava tube finds a lit walkway instead, which is safer but tamer.