MORE and nearly all the info you ask here is in the COUNTRY info-find it by a bit of clicking in the general site.

For summer you are WAAAAAAAY too early-trains are not planes, REServations is mostly only possible from 2-3, sometimes 4 monthes advance. There is also the summer timetable change hickup-railways will only open it when they are 123% sure of the new times (early june).

Besides that: do not despair, f.e. Par-Lyon has fast TGV-trains ev hour or so. OR you can use, without any extra to pay or even worry about seat/REServ. use the old style slower trains over the old rails (before they started building this hi-speed), ev 2 hrs, but that will take 5 hrs. Same-same for the locals from Marseille to Nice (I guess that is leg 2?). There is simply not (yet, maybe) a hi-speed line between these cities.

HINT/tip: use the travelplanner of bahn.de (=german railways) works for nearly all of EUR, is muchmore uptodate as the one in eurail and will tell very clearly if a REServ, is mandatory or optional.

You seem to be going other direction, but just in case; in ESpana its even worse as in FRance to make the REServ. for hi-speed trains.

Please specify the exact trains you would like to book a reservation for: origin, destination, date, departure time.

For some trains, it may still be too early, as mcadv said. But we need to see the details first to be able to say anything.

;the first train is the Paris to Lyon train on the 14th july at 10:10 and the second train is the Lyon to nice train on the 18th July at 11:36 . I can't buy the reservation for between Avignon to nice

There is no train to Lyon on 14 July that leaves Paris at 10:10. There is a TER (reservation-free) that leaves Paris-Bercy at 9:20 or a TGV from Paris Gare de Lyon at 9:58. Where did you find a train at 10:10?

The journey Lyon - Nice contains 2 TGV trains (and one reservation-free TER), which makes it a bit expensive. The second TGV, Toulon - Nice (arr. 16:07) only has seat reservations left for 20 €, and the Interrail website apparently still has problems with it (Belgian railways show it correctly). The total for this journey would be 30 € in seat reservations (34 if booked via Interrail). Why not use another connection, e.g. Lyon 9:40 - Nice 14:41 (TGV + TER, 1 change)? That would only be 10 € (12 via Interrail). Or the direct train at 14:04 (available for 10€).

As to Avignon - Nice: what date and departure time is that?

Hello, I’d like to add another question about this topic. I’ve read that we can only reserve a seat 3 months in advance. But in France train reservations for the summer started this morning (march 8th). I wanted to book a train on july the 17th between Toulouse (France) and Paris. And the return ticket on july 28th. What happens if the train we would like to take is oversold if we wait until the 3 months in advance? (ie: april 17th and april 28th for both journeys). Is there a way to make a reservation before the 3 months in advance to be sure we can have our reservation?

Thank you and have a nice day

The simple answer is that it is just not true what you did read. When the booking does open differs depending on the train company. When it's possible to do a reservation, you can do it. There is no three months rule.

Thank you for your answer. I tried again, but they don’t give me the option of booking seats on the interrail pass:

and when i click on “more info “ I have this information (regarding the 90 days max for a reservation):

I don’t know how to make the reservation; And since the tickets are opened on the regular SNCF website I hope there will be still seats left.

Reservation can be done here: https://travel.b-europe.com/Eurail-GE/en/booking-tgv#TravelWish

But it's cheaper to do it at a SNCF station if you do live in France. 

I tried that, but I have this answer:

and no earlier or later trains available on this specific website (while there are availabilities for that day on the SNCF website)

Just seems that SNCF (or SNCB) is a bit slow to open their booking for pass holders. Maybe you can try on the phone?

I tried that too.. i’ll retry later during the day..thank you for your answers! :)

I tried that, but I have this answer:

and no earlier or later trains available on this specific website (while there are availabilities for that day on the SNCF website)

I tried with your given date (17.7.) before posting. All trains are available. Did just verify.

I retried on my phone and on my computer; maybe I have an internet browser problem :(

i’ll see if I can use another computer somewhere, thank you!

Hi again, I tried on another computer but there is no option for buying a reservation seat. I tried both on my phone on the apps ans on the internet on interrail.eu and  https://travel.b-europe.com/Eurail-GE/en/booking-tgv#TravelWish .  I eventually called the SNCF by phone and we succeeded in making the reservations! I really don’t know why it’s been like this. now I suppose I only have to add manually the journeys on my pass (since they don’t appear and they can’t be added automatically). thank you for your help and have a nice day!

The app only updates once a month. The new schedules will not be uploaded yet. They will be in a couple of weeks.

We strongly advise NOT to activate a travel until just before taking your first train of the day. You’ll never know if something happens. It’s impossible to get travel days back, once the day started.

Hi thanks for your answer. I understand now why I couldn't see the trains (the apps updates once a month). But I’m not sure I understood the rest of your message. I think I already activated my pass but I’m not sure. What you’re telling me is that I should have bought the reservations in advance and later only when I’m a 100% sure of my travel days I should have activated my pass and declare my journeys? Here is the status of my pass:

Yes, you pass is already active, including 2 travel days. Just cancel both of them and them cancel the activation of the pass. Only activate again on your start day. Also note that adding a train to your pass in the app is not a reservation. Reservations are completely separate from the app.

@tchetchilia 

Are you travelling in France on both the travel days that you have activated on your pass? In that case you have no more travel days that you can use in your home country. 

Yes I’m travelling in France on both July 17th and July 28th. I already declared a couple of weeks ago my Paris London (outbound journey) and my London Paris (inbound journey) in my pass , because eurostar tickets can be reserved 6 months in advance (and should be reserved as soon as possible). And I just bought yesterday the Toulouse -Paris reservation on july 17th (for my outbound Journey: Toulouse Skegness (north of Engalnd) ans the Paris Toulouse reservation on July 28th (for my inbound journey: Brighton England-Toulouse ), because SNCF just opened yesterday sales on summer train tickets. I’m not sure to understand well. Event though I have activated those 2 days of travel (including outbound / inbound journeys) a couple of weeks ago, I can desactivate them today, and on July 16th (one day before my first day of travel) I can reactivate them? Which means I only have to buy mandatory reservations seats in advance in order to make sure I will have a seat,  and then declare the trains I’m using in my app just before travelling? It’s not easy to understand for me (as a non English speaking mother tongue), sorry 

Your understanding is correct - Reservations and you travel ticket (your pass) are indeed totally different and independent of each other, but to purchase some reservations you do need a pass that will be valid on the day - eg Eurostar bookings, but it doesn’t have to be activated until you actually travel.

For every train you travel on you simply need to add the details of the train to your trip and then on the day operate the slider for each train you travel on. These can be added right up to boarding (or similarly removed if you change your mind. This creates your travel day and displays a QR code and a listing of the trains you have now added from your trip. If you cannot find the train listed to add to your trip you can add the details manually - train number, time and start/end stations are adequate. Other than the max of 2 days where you can use the pass in your country of residence there is no restriction on the number of trains you can travel on (within the network). As long as you have validated the journey (i.e. QR code and train listed) you can travel on any included train - even if added at the last minute.

However some trains require a mandatory reservation and these need to be acquired (normally at an additional cost) separately and must be shown along with a valid travel “ticket” (i.e. QR code and listing). 

For trains with optional reservations you can travel on these just with your validated pass, but may need to stand or move seats if somebody with a reservation for that seat boards. For these you simply need your seat number to find your seat and eject any squatters, In the extremely rare occasions that a train with optional reservations would be unsafely overloaded persons without a reservation may be asked to leave the train.

As you will be travelling in UK, and maybe Ireland, for most of your trip it might be good to know that reservations in the UK are only optional, except for the night trains. It can be good to make reservations on popular routes anyway.

All optional reservation are free of charges if you make them with the railway companies.