See the answers in this thread posted just before yours for info on Paris - Geneve

Interrail and Swiss pass have different validity, both cover all normal trains in Switzerland, interrail offers some discounts on some tourist oriented travel such as ferries and some tourist rail.

Swiss pass covers more, buses, local transport, ferries and tourist things.

Neither will cover the whole Jungfrau trip, it is seriously expensive, even for Switzerland.

Another alternative you might want to consider is the half fare card https://www.sbb.ch/en/leisure-holidays/inspiration/international-guests/swiss-halffare-card.html, which is possibly also a bit more straightforward than some of the other options. Once you’ve paid the 120Fr. purchase price, it simply halves the cost of almost all public transport in the country, including single and return tickets for the Jungfrau region (it will almost pay for itself in one journey from Interlaken to the Jungfraujoch and back).

I've thought about it but the thing swaying me in the direction of the global pass is travelling from paris to geneve and then from interlaken to paris. 

Any tips on that please? Thanks a bunch!

This is my rough itinerary if it helps since im a bit confused.

1. Paris to geneve

2. Geneve to montreux for the panoramic train then to interlaken maybe

3. Jungfrau

4. Back to paris from interlaken

Ok, I’ve done a few quick sums:

Half-Fare Card 120 Fr.

Paris – Geneva c.€44

Geneva – Interlaken Ost via Golden Pass line 38 Fr. (I’m assuming here that the flexibility of not being tied to a particular train will be worth the 6-8Fr. extra over a Super Saver ticket to you)

Interlaken Ost – Jungfrau – Interlaken Ost 105.40 Fr.

Interlaken Ost – Basel c.21 Fr. (Super Saver) or 30.50 Fr. (standard flexible) & Basel – Paris c.€44

TOTAL: roughly 375 Fr. (CHF and EUR are very similar in value at the moment so won’t bother converting)

4-day Global Interrail Youth Pass €185

Paris – Bellegarde €10 + €2 booking fee (no booking fee at French stations but not really safe to leave until then as passholder places may run out, resulting in a €20 reservation fee which is obviously a false economy)

Interlaken Ost – Jungfrau – Interlaken Ost 158.40 Fr.

Frasne – Paris €10+€2

TOTAL: roughly 370 Fr.

3-day Swiss Travel Pass 232 Fr.

Paris – Geneva c.€44

Interlaken Ost – Jungfrau – Interlaken Ost 139.60 Fr.

Basel – Paris c.€44

TOTAL: too much!

The Swiss Pass option doesn’t make financial sense. The other two options (assuming you are under 28) are pretty similarly priced.

I would go for the Interrail Global Pass here because it will require fewer individual pre-bookings (and the prices of those you do make will be more predictable) and also because it will afford you a bit more flexibility. The only negative is that in order to attain the reasonable €10+€2 TGV reservation fees displayed here, you have to cross the Swiss border by local train.

If you’re 28+ however, the €60 extra charged for the Interrail Pass will probably make the Half-fare Card the best-value option fairly comfortably. The other scenario in which this option could reward you is if you decided to stay longer than one day around the Jungfrau; the Half-fare card is the only option of the three we have discussed with which you can get a discount (not half though, more like just over a third) on the multi-day Top of Europe Pass, which is already drastically better value than a return ticket, and will allow you to explore the whole area at your leisure, using all the trains, cable cars, funiculars etc: https://www.jungfrau.ch/en-gb/top-of-europe-pass/

Forget this HalbPreisKard-its useless for the normal tourist. Strange to list it as best answer.

There IS also a touristy half-fare card for 1 month-but I highly doubt if even that would help you very much.

IF you can preplan and book longer time advance for the 2 trips out of/to P,then book these for IN FR only via connect.sncf-can do til Gnv and FROm Basel (=both are border points for SNCF-not a lot extra to pay. For the trips i n CH-again IF you can preplan and know that it will be worthless if plans change: buy 2x the special dayticket via sbb for I thnk 59CHF-will cover both legs. Jungfrau is always extra and cost a lot. You may consider other trips up the mountain just as spectaculair (Jfr is mostly in tunnel) that cost less -there are plenty in this area.

The ALT would be the 4 day global, and again: do NOT use it for trip over border, these add a lot to the surcharges.

It is the latter of those two (the one month option) that I have been referencing. I initially only mentioned it as an alternative, but then later listed it at the second best answer in general, or the best for over-27s based on the calculations I did on SBB’s trip planner based on the stated specifics of this particular trip

sncf-connect.com was where I got the €44 figure from (for Paris-Geneva and Basel-Paris, both direct). Over the next two months or so the €44 fare is the more commonly available of the lower rates, and with advance booking should be fairly reliably obtainable. I thought it would be disingenuous to display the lower €33 or whatever, given I don’t know how early this trip is being booked or what time in the day Marwa may want to travel.

You are right on this - I somehow hadn’t realised that a Saver Day Pass without a Half Fare card didn’t cost double.  Because of this, and because the half-fare price over the next month was never any better than 49 Fr, I assumed - very wrongly - that this wouldn’t be a useful option. Also because none of the individual trips listed here (apart from the Jungfrau) are return journeys.

Let me just run the same scenario again with the benefit of this new-to-me information… (based on the assumption travel will be far enough ahead to always obtain the optimal 52 Fr. non-discounted Saver Day Pass)

Paris-Geneva €44 + Geneva-Interlaken 52 Fr. + Jungfrau 210.80 Fr. + Interlaken-Paris combined ticket c.80-85 Fr. (bought from SBB)

TOTAL: c.390 Fr.

So no, not drastically more, and yes, if the Jungfrau trip were swapped for something else, standard tickets and saver day passes would be the cheapest option here.

Yes, if viewed purely as a train journey the Jungfrau is not worth the money; though in some ways it is exceptional, and by whatever means you reach that kind of altitude it will always cost a lot, especially in Switzerland.

In a way, this is why I mentioned the Top of Europe Pass, which as well as being much better value (even without any discount at all, 3 days of unlimited travel throughout the valleys and mountains of the Lütschine costs only 40 Fr. more than a return ticket to the Jungfrau), also gives you more of an opportunity to experience the region more fully and reach the several areas and villages unaccessible by car or bus.

Alternately though, you might consider simply foregoing all that expense and just taking the vintage rack railway up to Schynigge Platte (64 Fr. return or 48 Fr. with an Interrail discount). It’s nowhere near as high as the Jungfrau, but that means that once you arrive at the top, the wonderful natural environment you encounter is much more usable, and you can go for a delightful stroll through alpine meadows, from which you can see the valleys opening up in all directions (Lakes Brienz and Thun are both visible to the north, and most of the major mountains in the Grindelwald and Lauterbrunnen areas are visible to the south). You’ll also hear plenty of cowbells and see a fairly expansive and free to enter alpine botanical garden.

If you are a fan of James 007 Bond you might want to go to Schilthorn where parts of a Bond-movie was filmed. There is a turning restaurant at the top and the view is very nice. 

https://schilthorn.ch/en/Infos/Timetable__and__Tariff

It is rather expensive, but not as expensive as the journey to Jungfrau.