If you If you plan to rent a car in Japan, you’ll quickly notice three fuel options at gas stations:

• Regular (レギュラー)
• High-Octane (ハイオク / Premium)
• Diesel (軽油 / Keiyu)

Choosing the wrong fuel can cause serious engine trouble. Here’s a simple guide to help you refuel safely in Japan.

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1. Regular Gasoline (レギュラー)

Japanese label: レギュラー
Octane rating: Around RON 90–91

This is the most common gasoline in Japan.
Most compact cars, economy cars, and standard rental cars use regular gasoline.

Typical Cars:

• Toyota compact cars
• Nissan small cars
• Honda Fit class vehicles

If you rent a small or standard car in Japan, it almost always uses Regular.

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2. High-Octane Gasoline (ハイオク / Premium)

Japanese label: ハイオク
Octane rating: Around RON 98–100

High-octane fuel is for high-performance or luxury vehicles. It prevents engine knocking in powerful engines.

Typical Cars:

• Sports cars
• Luxury brands like BMW, Mercedes-Benz, and Audi
• Some turbocharged engines

If your rental car requires high-octane, it will clearly say so on:

• The fuel cap
• The rental agreement

⚠️ Do not use regular gasoline in a car that requires high-octane unless the manufacturer states it’s acceptable.

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3. Diesel (軽油 / Keiyu)

Japanese label: 軽油 (Keiyu)
English label at stations: Diesel

Diesel fuel is used in diesel-engine vehicles, which are common in:

• Vans
• SUVs
• Trucks
• Some European cars

Diesel engines are fuel-efficient and popular for long-distance driving.

⚠️ Important:
In Japan, “軽油” literally means “light oil,” but it does NOT mean “light gasoline.” It is diesel fuel.

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Which Fuel Should You Use?

Here’s a simple rule:

Your Car Type	Fuel Type
Most small rental cars	Regular
Luxury / sports cars	High-Octane
Diesel vehicles (written “Diesel” or “軽油”)	Diesel

✅ Always check:

• The sticker inside the fuel door
• The rental contract
• Ask the rental staff if unsure

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What Happens If You Choose the Wrong Fuel?

• Gasoline in a diesel car → Engine damage (very serious)
• Diesel in a gasoline car → Engine trouble, possible breakdown
• Regular instead of high-octane → Reduced performance, possible knocking

If you make a mistake, do not start the engine. Call the rental company immediately.

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How Japanese Gas Stations Work

There are two types:

1. Self-service (セルフ)
2. Full-service (staff refuels for you)

If you’re unsure about Japanese labels, simply say:

“Regular, please.”
“High-octane, please.”
“Diesel, please.”

Or show the fuel cap to the staff.

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Final Tip for Tourists

In Japan, fuel nozzles are usually color-coded:

• Red → Regular
• Yellow → High-Octane
• Green → Diesel

(Colors may vary slightly by brand.)

If you are renting a car for sightseeing in places like rural areas or highways, double-check before pumping. A simple mistake can cost a lot.

When in doubt — ask first.

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