Chiasso is the border point. The GA is valid until there and then the One Country Pass is. No need to buy a special ticket.

Keep in mind that you need a 10€ seat reservation on Frecciarossa trains (and 11€ for EC) and 3€ for IC trains in Italy.

I'd advise to take the RE between Lugano, Chiasso and Milan. It doesn't take longer and is reservation-free :)

To buy reservations in Italy : tickets.oebb.at -> add Interrail as a discount and select one-way tickets

Trenitalia tickets can be very cheap in advance so have a look first at Chiasso - Rome fares Often 1st class is cheaper than 2nd

Same at Domodossola, you can get with GA to Domodossola from there your Interrail One Country Italy is valid.

Thank you so much for the answer and advise!

I looked at the prices on trenitalia and even by travelling at inconvenient times and buying the 30 euros ticket Chiasso - Roma to go and come back two times it would be minimum 120 euros, which is not that far from the 139  euros 4 days one country interrail pass whihc would also allow me to travel at better hours .

I am planning to take the RE to Milan from Bellinzona :) 

Yes but you need to add 4 x 10€ for the Frecciarossa train between Milan and Rome as it is a mandatory seat reservation -> so 179€ in total

What would be your travel dates ?

I thought that by buying the ticket from trenitalia I would still need to pay for the seat reservation separately, as it is usually not included in the ticket price. Anyway if I would want to get to Rome as early as possible on Saturday and go back on Sunday aftenoon / evening to where I live the connections are pricier, because I guess that they are the most requested times. I would probably go the weekends 20-21 May and 3-4 June

Hi, no on trains with compulsory reservations, you get the seat reservation with point to point tickets for free.

Thank you for the info! That makes sense, I will calculate prices again then!

It's true that Saturday mornings and Sunday evenings are quite busy…

So yes I believe a One country pass will be worth it in the end for your dates. 179€ incl. seat reservations while one return ticket would already cost 150€…

Book the seat reservations on tickets.oebb.at so you avoid the booking fees

Frecciarossa high-speed trains are great so you'll enjoy a lot of time with your boyfriend :)

- Bellinzona 05:17 (early departure) -> Rome at 10:40 or 11:10

- Leaving Rome at 16:25, you arrive in Bellinzona at 21:16 (or later departures but they take a bit longer)

You could even leave Bellinzona at 17:44 on Friday evening and arrive at 22:34 in Rome or take the night train leaving Milano Porta Garibaldi at 22:13

Thank you so much! I will take a connection that arrives earlier on sunday because I will need to go back to where I live, which is one hour away from Zurich, on friday/saturday i would start from Locarno.

I am excluding the night train if I want to use the one country pass as I would need to use two travel days

You don't use a second travel day as long as you board the last train before midnight :)

So only Friday would be used as a travel day and you arrive in Rome at 06:00 Saturday morning

On the FAQ I read that that is valid only with the global pass, not with the one country pass

This rule seems weird to me. Maybe the FAQ hasn't been updated ? Could you please link the page where you've found the info ?

I read them again and my bad, they wrote that you need the global pass to go on cross border countries night trains, so I think I could go on the night train from Switzeland to Italy with my Swiss abonnament and the one country pass.

Yes exactly. You could take the night train from Milano Porta Garibaldi. However advance tickets are often cheaper than the supplement for a couchette/sleeper…

That depends a bit on what type of pass you have and what accommodation you want to book. Single sleepers supplements are quite expensive and advance tickets are cheaper but for other accommodation you really need to make the calculation, also depending on whether you use the pass for more trains before the night train.