INTERRAIL FOR MY SON

is valid to take the metro in this cities? are special prices in bus?

Interrail is not valid on metro or buses, apart from railreplacement buses.

Only trains of the bigger train companies are included in the interrail pass.

Transport in cities like metro/u-bahn, tram, bus are considered as local transport and are not included in the pass. Tickets only cost a few euro’s anyway, especially when young. Most city public transport have generous discount for younger people.

If his itinerary is entirely by train:

1. Hendaye-Ámsterdam

2. Amsterdam-Berlin

3. Berlin-Prague

4. Prague-Budapest

5. Budapest-Split (assuming a night train on this route?)

6. Split-Hendaye

He'll need 7 travel days as an absolute minimum, as it is impossible to reach Hendaye from Split in a single travel day, you'll need a minimum of 2 and maybe even three: it really is quite a long trip. 

On the other hand, a Berlin-Prague or Prague-Budapest ticket might be cheaper than the extra of a 10-day pass. The 10-day pass does have the advantage that it's travel days can be spread over a 2-month period.

Thank you very much for your comments. Can you think of a better combination to be able to do this whole itinerary by train?

if not, My son will have to return by plain, split bilbao, Finally he bought a 5 days plan

Then he will have to calculate which day he uses the pass, which day he gets separate tickets.

Definitely use Interrail for Hendaye-Amsterdam and Stuttgart-Hendaye (more below). For the rest it depends.

For the big Split - Hendaye journey I can think of this good itinerary:

DAY 1

- Split - Zagreb daytime train 08:01 - 16:20 + delay

- Zagreb - Stuttgart EuroNight 19:38 - 08:38 (couchette)

DAY 2 (Interrail)

- TGV Stuttgart Hbf - Paris-Est 09:10 - 12:32 (he could already board it in Augsburg or Ulm if the slower EN is delayed)

- (across Paris by subway)

- TGV Paris-Montparnasse - Hendaye 14:05 - 18:47

Perhaps he could travel with tickets on Day 1 but on Day 2 Interrail will be really good value (even including the 18€ reservation for Stuttgart-Paris + 10-20€ for Paris-Hendaye).

Train times are not definite for July.