How far in advance can I order an Interrail Pass?

The earliest in advance you can order an Interrail Pass is 11 months before you start your trip.

When you order your Interrail Pass, you'll need to enter the date when you want to start travelling with your pass. This date is printed on your Interrail Pass as your start date. You can order your pass anywhere within the 11 months before this date.