Iceland's F-Roads: Driving the Highlands in a Rental 4x4

In Iceland, any road numbered with an 'F' prefix (F35, F208, F249, F26…) is a highland track: unpaved, often narrow, sometimes little more than two ruts through lava or volcanic ash, and closed to traffic for a good part of the year. It differs from 'ordinary' gravel roads on the secondary network (numbered without an F, like some Westfjords tracks) through one simple but strict rule: driving is banned for anything that isn't four-wheel drive, and most rental companies spell this out explicitly in their contract.

Iceland's highlands have no petrol stations, no reliable mobile signal, and no nearby help: a mechanical issue or a run off the track rarely gets sorted in under several hours. It's terrain that rewards preparation and punishes improvisation — unlike the Ring Road, where a bit of slack in the plan is usually forgivable.

No F-road has a carved-in-stone opening date: Iceland's Road Administration (Vegagerðin) inspects each stretch after the snow melts and decides, route by route, when it becomes passable. In practice, the more accessible tracks like F35 (Kjölur) usually open first, in late May or early June; the busy classics toward Landmannalaugar (F208) or Þórsmörk (F249) follow in mid to late June; the most remote interior — Sprengisandur (F26), Askja, Kverkfjöll — often doesn't open until early July, sometimes later after a particularly snowy winter.

Closing happens in reverse with the first autumn snow, usually in September. Between those two bookends, the only reliable truth is the one for that specific day: the official site road.is shows each route's status — open / closed / impassable — and umferdin.is adds real-time conditions. Checking both before setting off — not the night before, the morning of — is one of the non-negotiable habits of a highland road trip.

Icelandic law reserves F-roads for four-wheel-drive vehicles, and rental companies translate that into an unambiguous contract clause: taking a sedan or a 2WD rental onto an F-road risks a fine, but more importantly voids insurance cover entirely if anything goes wrong — the contract treats the driver as being in breach, regardless of what actually happened. It isn't an optional checkbox; it's written into the terms of nearly every rental company in the country.

Not all 4x4s are equal on the toughest F-roads either. A compact rental 4x4 (think Dacia Duster or Suzuki Jimny) is plenty for F35 or, in dry conditions, F208, but the deepest fords on Sprengisandur or the track to Askja demand ground clearance and wading depth that only larger 4x4s or modified 'superjeeps' (oversized wheels, lifted suspension) genuinely provide. Checking with the rental company exactly which F-roads are explicitly permitted with the booked model avoids a costly surprise on the ground.

The basic collision damage waiver (CDW) included in most Icelandic rentals excludes gravel-related damage by default: a cracked windscreen from a stone, scratched bodywork, an undercarriage scraped on a rocky track. Covering that very real risk on an F-road requires a dedicated add-on, usually called Gravel Protection (GP), which reduces or removes the excess on this specific type of damage.

One point is worth repeating exactly as it appears in almost every Icelandic rental contract, with no paid option to insure against it: damage from water entering the engine during a river crossing is never covered, by any insurance, at any price. A flooded engine from a badly judged ford stays entirely on the driver's tab, and repairing a small 4x4 can run into the thousands of dollars. It's the most universal clause in the industry — and the real reason nobody crosses a ford casually.

A ford ('vað' in Icelandic) is negotiated with method, not instinct. First, spot a crossing already used by other vehicles — tracks in the riverbed suggest a relatively stable bottom — and if there's any doubt about depth, walk it first with a stick to check before committing the vehicle, not after. Morning remains the safest time: glacial melt, weaker after a cool night, generally keeps river levels lower before afternoon heat pushes them back up.

Once committed, shift into 4x4 mode (often 4L on unstable ground), hold a low but steady speed, and never stop mid-current — stopping is exactly what lets water seep in and the vehicle sink. When there's serious doubt about whether a crossing is feasible, the best call is often to wait for another vehicle, ideally one riding higher, and watch its crossing before attempting your own — or simply turn back: no highland view is worth a flooded engine hours from any help.

A study by Auður Tinna Arnadóttir, Gudmundur Freyr Ulfarsson and Sunghoon Kim, published in 2025 in the journal Traffic Safety Research, analysed single-vehicle crashes on Iceland's rural roads and confirmed something rental companies have said for years: being a foreign tourist driver noticeably raises the odds that a crash turns severe, largely because these drivers underestimate conditions unfamiliar to them — unprotected roadsides, single-lane bridges, or, in this case, deep gravel and fords (study available on Google Scholar: scholar.google.com/scholar?q=Arnadottir+Ulfarsson+Kim+single-vehicle+injury+crashes+rural+roads+Iceland). The study covers the country's paved network, but its lesson carries straight over to F-roads, where the gap between what a visitor expects and what the terrain actually delivers is even wider.

In practical terms, that translates into one useful rule for planning a road trip: never treat an F-road as a scenic variant of the Ring Road, but as terrain that demands slowing down, checking the day's conditions, and turning back without hesitation the moment doubt sets in.

Worth checking in a few minutes before turning onto the first F-road of the trip.

The 'Self-Drive Iceland' guide devotes a full chapter to the highlands: which F-roads stay reasonable with a compact rental 4x4, which ones call for a superjeep, and how to read glacial-melt forecasts before committing to a ford. Enough to decide calmly between Landmannalaugar and an extra detour along the south coast if the day's conditions don't cooperate.