Hi @Alizee Maille  Welcome,

This is the Community  and if you share few details of your Route you will get replies and suggestions for your Route and maybe even some ideas to extend your Route or to make the best out of your Railpass. 

Informations needed to give good suggestions and advices :)

Which Route do you have in mind? (Cities/Countries)
or if not sure what kind should be your trip? (Cities,Nature,Mountains,Coasts ?)

Which pass you have or consider to use :)

The Community is here to help you and maybe give sometimes guidance or a advice. The community is moderated by the staff of Eurail the company behind the Eurail and Interrailpass but many here are travelers like you and i and are here to share their knowledge or getting new ideas.

I traveled few years with Groups through Europe useing Interrailpass,Eurailpass,EuropeanEastPass or German Railpass. As iam working now for DB (German Rail) i travel qutie alot through Europe by rail as it is my job and my passion .

Thanks you for answering me ! 
I would like to start my trip from Paris then Berlin to vienne, vienne to Venise (but I would like to stop to Salzburg because the time is shorter to Salzburg-Venise than vienne-Venise) after it’s Venise to la spezia, la spezia-Rome, Rome-ancone and after I take the ferry to go to Greece ! 
i plan à trip for three weeks, and I’m going to take a global interrail pass. I have 7 days of trip in three weeks. 
What are you thinking about this ? 

Travelday 1 Paris - Berlin you will need atleast one Reservation on top of the pass 17€ in second class for the ICE/TGV (High Speedtrain) from Paris to Germany (Frankfurt/Mannheim) here you have connecting trains to Berlin :)  Will be a long travelday

Travelday 2 Berlin - Vienna i recommend to take the early at 6am Railjet that goes via Dresden,Prague and Brno (Maybe add Prague as stop and catch from Prague to Vienna the cheap trains of Regiojet from just 18€ often even last minute they bring you to Vienna for 35€ you can travel in their business class. )

Other options are a direct ICE via Nürnberg or a direct Nighttrain

Travelday 3 Vienna - Salzburg (you can use a travelday of your pass or you use the cheap tickets of Westbahn and use the travelday to add a stop) 

Travelday 4 Salzburg - Venice direct Nighttrain or daytrains with a change in Villach or Innsbruck both Routes are scenic note that on the Routes to Venice Railpassholders have to pay a surcharge of 10€ in 2nd class or 15€ 1st class

Travelday 5 Venice - La Spezia i would do a bit of a detour and go from Venice via Milan,Genoa to La Spezia note that Italian Highspeed trains need a reservation of 10€ per train.

Travelday 6 La Spezia - Rome i recommend to take the direct Intercity along the Coast (a bit slower but worths the timeloss)

Travelday 7 Rome - Ancona - Ferry to Greece Here the Ferries that offer discounts or are for free (depending on the pass you use and what comfort level you prefer for the Cruise)  Other Harbours are Venice or Bari with ferries to Greece :)

 

Hey thanks to take some time to answering me, but sometime where I search trains on interrail, I found free trains from Vienna to Venice, or even from Venise to la spezia.

So do I have to reserve my place on interrail or go to the trains website ?

There are different ways to reserve the trains which you can use depends from the Country where you are and which train you will take

My order if possible

1st On the operating Traincompanies website

2nd At a international ticket office next to me :)

3rd by phonecall to the Call Center of the Company

4th At a station in the country where this trains operate

5th The last option a reservation service like Interrails own, Raileurope, ACP Rail and many many more as these charge on top of the Reservation a service fee in case of Interrail the service fee is charged on top of the reservations per train. :/

 Vienna - Venice can be done online on oebb.at please note that the Vienna - Venice train needs a surcharge of 10€ 2nd Class or 15€ 1st class if you pay this fee at a Austrian Ticket Office in Austria you get with this fee a seat reservation for free. If you pay it Online you pay the Surcharge + 3€ for the seat. Last Option is to get the reservation if you want one in advance for 3€ and pay the surcharge onboard of the train.


Vernice - La Spezia is quite hard as Trenitalia stoped to sell Interrail reservations on their page back in 2019 Bestway here is a ticket office next to you or a Reservation service like Interrails own or  ItaliaRail.com

but I don’t understand, why I can’t make a train reservation on interrail ? why I have to make a reservation on the train website ? 

Ofcourse you can make  almost all reservations via Interrail but they do nothing else than useing the Trainoperator website or the booking system of the operating train company and charge for that a service fee. (The staff behind the Interrail Reservation service need to be paid) Because of that @rvdborgt  @runner.on.rails  and I prefer to reserve directly with the Railcompanies if possible, as it´s cheaper and you often can select a specific seat from a Carriage Layout :)

In Countries like Germany,Switzerland,Austria, Czech Republic are reservations a optional service (you can reserve but it´s not compulsory) and quite cheap 3-5€ :)

Interrail is a own company (Eurail B.V. from the Netherlands) that offers the Pass (They have contracts with the operating traincompanies). Some Companies said they wanna control how many passengers will be on a specific train and said that you need ontop of the pass reservations Over the years they noticed that they can earn some money with reservations on top of the Money that they get from Eurail B.V. and started charging for Reservations.