Before reserving or before departure… We advise all of our traveling companions to be in control of their own documentation. It may sound silly, but we don’t want to leave people at the border because they don’t have all the documents they need.
Each country has different rules for different nationalities, so we advise you to find out if a national identity document (drivers’ license for example) is sufficient to enter into all the countries we will be going to, or if you will need extra documents such as:
If you are an EU citizen you have it very easy, normally it is possible to travel across all 26 EU countries with national ID (though why not bring your passport just in case?!)
If you are a citizen outside the EU it can get complicated, so check, double check, and check again!!