InterRail - WHO can buy
The InterRail pass is only available for European citizens and Non-Europeans who stayed more than 6 months in one European country. The stay has to be proved by official documents such as a visa or residence permit.
The following persons are allowed to buy an InterRail pass and to travel by InterRail.
You can buy an InterRail Pass if you have had your permanent place of residence in one of the following European countries for at least the past 6 months.
If you do not have an ID card or a passport issued by one of the countries mentioned above, you will have to prove your current place of residence by producing a visa or residence permit.
If this doesn't apply to you, you will have to buy a Eurail pass.