In Europe, Australia, and New Zealand, 98 octane (RON) is widely available at major service stations as "Premium Unleaded."
Most standard vehicles, like a Toyota Prius or Honda CR-V, are optimized for 87 octane and will not see a performance benefit from 98 octane. SS 100 - 100 Octane Unleaded Gas - Sunoco Race Fuels where to buy 98 octane fuel
If you truly need 98+ AKI for a high-performance or tuned engine, you often have to look for "Race Gas" at specific retailers. In Europe, Australia, and New Zealand, 98 octane