Driving in Rural Shikoku: Narrow Mountain Roads, Fuel, Parking and the Rules (A Local’s Guide)

Quick answer: Keep left, stop completely at every railway crossing and “止まれ” sign, and never turn on red. On one-lane mountain roads, drive slowly, watch the curve mirrors, and be ready to back up to a passing place. Fill up when the tank is half empty — rural petrol stations close early. Check for rain closures before heading into the Iya Valley, and zero alcohol if you’re driving.

Driving is the best way to see rural Shikoku, and most of it is easy: quiet roads, polite drivers and free parking at most sights. But the mountain roads can surprise visitors. I live in Tokushima and drive these roads myself — the roads around the Iya Valley and Oboke and towards Mt. Tsurugi still make me careful. This is what I’d tell a friend before they set off.

The basic rules

• Drive on the left.
• Speed limits: 60 km/h on ordinary roads and 100 km/h on expressways unless signs say otherwise. From September 2026, the default on roads with no centre line is 30 km/h — that includes many rural lanes. Signs always take priority.
• Stop signs (止まれ) are red, upside-down triangles. Come to a full stop.
• Railway crossings: stop completely before crossing, even if the barrier is up and no alarm is sounding.
• No turning on red — not even left. Only a green arrow lets you go.
• Seatbelts for everyone, front and back. Child seats for children under 6.
• Phones: holding one while driving costs ¥18,000 and penalty points; causing danger with one is a criminal offence.
• Alcohol: don’t drink at all if you’re driving. Penalties are severe — and passengers, whoever served the alcohol and whoever lent the car can be punished too.

Mountain roads: the part that needs care

Some of Shikoku’s national routes shrink to a single lane in the mountains, with sharp bends, steep drops and no centre line. Route 439, which runs through the Iya area, is famous in Japan as one of the toughest national roads. I’d count the roads around Iya and Oboke, and towards Mt. Tsurugi, among the ones where you need to concentrate.

Passing oncoming cars

On one-lane roads you’ll regularly meet a car coming the other way. Japan’s official driving manual advises:

• The downhill car gives way to the uphill car.
• If there’s a passing place (待避所) near you, pull in and wait — even if you’re going uphill.
• On a cliff-edge road, the car on the cliff side stops.
• Don’t drive too close to the edge; the shoulder can crumble.

In practice, be ready to reverse to the last wider spot. Local drivers do this all the time, and a small car makes it far easier. See Renting a Car in Shikoku for why I recommend one.

Blind corners

Use the round curve mirrors at blind bends, but remember they make distances look longer. You only have to sound your horn where a “警笛鳴らせ” (sound horn) sign is posted; elsewhere, use it only to avoid danger.

Animals

Deer and wild boar often run onto mountain roads, especially at dusk and at night. Slow down after dark. If you hit an animal, stop safely, turn on your hazard lights and call the police (110) — it’s required, and your insurance needs the report. Stay in the car if a large animal is still alive.

Rain, rockfalls and road closures

After heavy rain, mountain roads get rockfalls and fallen trees, and some sections close automatically. For example, on the Kochi side of the Iya area, Route 439 closes once rainfall reaches set limits, and Route 32 through the Oboke gorge closes above 250 mm.

• Check the forecast before driving into the mountains, and avoid them in heavy rain or typhoon warnings.
• Tokushima Prefecture and the national highway offices post closure information online (in Japanese — a translation app helps).
• If you see small rocks on the road, there may be bigger ones round the next bend. Slow down.

Winter

From December to March, snow and ice can close high roads, including routes towards Mt. Tsurugi. Rental cars usually come with normal tyres, so if you’re planning mountain driving in winter, ask for winter tyres when you book, or stick to the main valley roads.

Fuel

• Rural petrol stations close early, and some close on Sundays. My advice: fill up when the tank is half empty, and don’t head into the Iya Valley on a low tank.
• Self-service stations show “セルフ”. Touch the static pad first, then use the red nozzle for regular petrol (yellow is high-octane, green is diesel). Stop when the nozzle clicks.
• Kei cars run on petrol, not diesel — 軽油 (keiyu) means diesel.
• Return a rental car full.

Parking

Most rural sights have free car parks. In towns and cities, you’ll use coin parking:

• Flap type: park in a numbered bay; a metal flap rises under the car after a couple of minutes. When you leave, enter your bay number at the machine and pay, and the flap goes down. Never drive over a raised flap.
• Gate type: take a ticket on the way in, pay at the machine, then drive out.
• Camera type: enter your number plate at the machine.

The flap type confuses many first-timers — just remember your bay number.

Illegal parking fines are ¥15,000–18,000, and rental companies add their own charge if you don’t pay.

In the city: Hiroshima’s streetcars

If your trip starts in Hiroshima, watch out for the streetcars (trams). They share the road with cars on many main streets, and you’ll find yourself driving alongside them, with tracks in the middle of the road and passengers crossing to the tram stops. Take your time, follow the signals and lane markings, and don’t stop on the tracks.

Expressways

• Slow to 20 km/h or less in the ETC lane. If the bar doesn’t open, don’t reverse — stop and use the intercom.
• Parts of Shikoku’s expressways are two-lane, two-way sections with lower speed limits and no central barrier. Obey the signs.
• Fill up before long expressway stretches; not every rest area has fuel.

Navigation

Google Maps works well, but it sometimes picks very narrow back roads as the “shortest” route. In the mountains, stick to numbered routes where you can, and download offline maps — signal is patchy in the Iya Valley.

Emergency numbers

Your rental papers will also have the company’s own roadside number.

FAQ

Is it safe to drive to the Iya Valley?
Yes, if you drive slowly, use a small car, avoid heavy rain and go in daylight.

Do I need to honk at every bend?
No — only where a “sound horn” sign is posted.

Can I have one drink?
No. Any alcohol is prohibited when driving in Japan.

Kaz

Tokushima local with family roots in Hiroshima

I live in Tokushima and my family is from Hiroshima, where I also used to live. I still go back several times a year. The guides here come from places I have actually been. Where I haven't tried something myself, I say so.