Helmet, headlamp and crampons, a certified caving guide, and entry to the protected tunnel section. Hot cocoa is served at the trailhead once you resurface.

At your confirmed time, meet your Northlight Voyages guide and small group at the Selskarð lava tunnel car park. Wear sturdy shoes and warm, waterproof layers — the tunnel holds a steady 4°C year round.

Your guide hands out a helmet and light before leading you underground. Listen as they pick out the tunnel’s strangest features and explain why the lava rock shifts colour as you walk. Loose boulders make a few stretches slow going, but a footbridge and a set of graded paths cover the roughest ground. Lamps have been placed to bring out those colour changes and to show just how much force the eruption carried when it hollowed the tunnel out — the Hraunvík event, roughly 4,800 years ago.

When the tour wraps up you are free to make your own way back to the harbour town or carry on to your next stop.

Meet at the Selskarð tunnel car park, 34 km east of the harbour town. Tours end at the same point roughly 2 hours 40 minutes later.

The tunnel floor is uneven and includes two staircases, so it is not suitable for wheelchairs or prams. Travellers should be able to walk 1.4 km over loose rock.

Minimum age 6. Maximum group size 14. Tours run in light rain and snow; they are called off only for flood warnings inside the tunnel.

Cancel up to 24 hours before the start time for a full refund. Cancellations inside 24 hours are refunded at 50%.

Helmets and lights are sanitised between departures. Guides carry a first-aid kit and a radio; mobile signal drops out about 60 m into the tunnel.

Common questions on parking, luggage storage and what happens if your flight lands late are answered here.