Askja Caldera

Askja is a set of nested calderas in the Odadahraun lava desert north of Vatnajokull, formed by a series of eruptions culminating in a huge collapse in 1875. Inside sit two lakes: Oskjuvatn, Iceland's second-deepest at 220 m, and the smaller Viti explosion crater, which holds a milky blue lake at around 22°C where visitors have long stripped off for a swim. The landscape is so barren that in 1965 and 1967 NASA sent the Apollo astronauts here to practise moon geology; the ground crunches like slag and stretches empty in every direction.

The visit is a big day. From the Dreki hut car park, a 2.5 km gravel track climbs 100 m to the caldera rim, then a steeper path descends to the Viti crater. Bathing has been restricted in recent years due to unstable slopes; check the sign at the warden hut. The wider caldera walk to Oskjuvatn shore adds another hour. In late 2021 a landslide sent a small tsunami across Oskjuvatn, and the ground has been monitored for renewed unrest since; follow the current warnings.

Getting there is the hard part. F88 from Ring Road via Herdubreidarlindir is 90 km of gravel with river fords; F905 and F910 from the north are easier but longer. Only a proper 4x4 with river-crossing insurance qualifies. The simplest option is a full-day super jeep tour from Myvatn (roughly ISK39000). Fuel, food and water: bring everything. The Dreki hut sleeps 45 and books out fast in July. Weather is highland weather: sun, sleet or fog, sometimes in one hour.

The turn for F88, signed Oskjuleid, leaves Route 1 at Hrossaborg, a horseshoe-shaped tuff crater about 30 km east of Reykjahlid, and that is where tarmac ends for the rest of the day. The track runs south along the west bank of Jokulsa a Fjollum, passes the oasis of Herdubreidarlindir at roughly the halfway mark, and reaches Dreki after 90 km of washboard, blown sand and two fords: Grafarlandaa, usually shallow, and Linda, the one that turns cars back. Allow three and a half to four hours each way and do not plan on averaging more than 40 km/h. From Dreki a short spur, F894, climbs around 8 km to the Vikraborgir parking area where the walking starts. Check road.is and safetravel.is the morning you set out, cross the rivers early before afternoon meltwater peaks, and if either ford looks doubtful, turn around: there is no recovery service out here.

Nothing is charged to walk in. Askja lies in the northern territory of Vatnajokull National Park and there is no gate, ticket desk or ranger toll; the ISK1000 at Dreki is parking only, paid at the hut. Every other cost is transport. A Land Cruiser-class 4x4 cleared for F-roads runs roughly ISK30000 to ISK45000 a day in July and August, and the round trip from Reykjahlid burns something like 40 litres, close to ISK12000. A guided day trip at about ISK39000 removes the rental, the fuel and the risk of a drowned engine, which no Icelandic policy covers: water damage is excluded from every CDW, gravel and sand package sold. A sleeping-bag bunk at Dreki costs in the region of ISK10000 and camping around ISK2500. Buy food in Reykjahlid, because there is nothing to purchase between the Ring Road and the caldera.

The season is ten weeks. F88 typically opens between 20 and 25 June and closes with the first serious snow in early September, later in a dry summer, weeks later in a snowy one. Mid-July to late August is the dependable window: the snowfields across the Viti path have melted, rivers have dropped from the spring peak, and wardens are posted at Dreki and Herdubreidarlindir. Within the day the pattern is predictable. Guided jeeps and the Reykjahlid bus reach Vikraborgir between roughly 12:30 and 14:30, and for those two hours the rim is crowded by highland standards, which means perhaps forty people. Leave Myvatn at 07:00 and Viti is yours around 11:00. Better still, arrive at 18:00 in early July, when the midnight sun holds the caldera in light past 23:00. Fog is the wildcard and no forecast handles it; go on the clear day, not the planned day.

Suitability is blunt here. There is no wheelchair or pushchair access of any kind: the 2.5 km to the rim is loose pumice and gravel with a 100 m climb, and the drop into the Viti bowl is a steep, greasy clay slope of about 60 m that is genuinely slippery in rain. Children under ten will find eight to twelve hours of vibration on gravel unbearable, and there are no toilets between Dreki and the trailhead. Anyone prone to motion sickness should take something before Hrossaborg, not after. Teenagers who like volcanoes and moonscapes do well, and photographers get more from this than from anything else within 200 km. If you have only one day based at Myvatn, spend it on Dettifoss and Krafla instead: there is no short version of Askja, no half-day option, and no way to squeeze it into an afternoon.

Fold in what sits along the same track. Drekagil, the dragon gorge directly behind the hut, is a 30 to 40 minute return walk to a waterfall at its head and is the obvious way to fill the wait while a group regroups. Herdubreidarlindir, 35 km back up F88 and about an hour of driving, has spring-fed streams, a campsite and Eyvindarkofi, the turf shelter of the outlaw Fjalla-Eyvindur, ten minutes from the car park under Herdubreid itself. Drivers coming out on F905 pass Modrudalur on Route 1, Iceland's highest working farm at 469 m, where Fjallakaffi serves lamb soup and flatbread and is the only hot food for hours. Back at Myvatn, Krafla's own Viti is free and roadside with no bathing, Hverir steams beside Route 1, and the Nature Baths at around ISK8000 are the right end to the day.

Two things are oversold. The first is the swim: brochures still lead with steaming blue water, but the descent has been closed or discouraged repeatedly since the slope instability came to light, and even when open there is nowhere to change, the water smells strongly of sulphur, the bottom is grey clay and the climb back out in wet clothes is unpleasant. Oskjuvatn is not a substitute; it is near freezing and off limits. The second is the colour. In flat light the crater reads dull grey-green, not turquoise, and in fog you drive eight hours to see forty metres. Nobody warns visitors that Askja is under geodetic monitoring for inflation and that the park can restrict access at short notice. Treat the drive as the attraction, keep a spare half-day in the schedule, and accept that a good Askja day is partly a matter of luck.

Hours & entry

Free; ISK1000 parking at Dreki hut

Accessible late June to early September only · Dreki warden hut daily 8:00-22:00 in season · Viti lake open 24/7

What to see

• Viti crater lake viewpoint — Rim above the crater, 2.5 km from Dreki hut
• Oskjuvatn shore — Trail continuing west of Viti along the caldera floor
• Herdubreid table mountain — Visible from F88 approach; classic photo stop at Herdubreidarlindir

Tips from the ground

• Take a super jeep tour from Myvatn unless you are experienced with river fords
• Check the safety board at Dreki hut for the current Viti bathing status
• Fill the tank in Reykjahlid; there is no fuel for 200 km round trip