Train from Paris

Your need for a pass will be guided by your entire Swiss itinerary. Can you fill us in on where you are staying and how many nights in each place? What activities do you have planned?

You do not say where in Switzerland you are going. The Family Card and Half Fare Card only kick in once you are in Switzerland, so they do not help going from Paris to Basel (assuming that is the way you are going), but the kids will travel at half price.

Sorry! We are traveling from Paris to Wengen and will stay in Wengen for 2 nights - quick stopover. We plan to do some easy hiking, see waterfalls, but would appreciate any other recommendations!

You can buy the ticket Paris - Wengen (and Wengen to wherever your next stop is) on www.sbb.ch just fine. The site does indeed ask you if you have a pass or a reduction card, as those will reduce the cost of the ticket. But those passes/cards are not compulsory.

Depending on what you plan to do getting the Swiss Half Fare Card may be a good option. With that card (and the free Family Card you get with it) the adults travel half price, and the kids for free in Switzerland. Saves you a whole lot if you wanted to do a mountain excursion. The price is 120,- per adult, so it is an up front investment, and wether it is worth it for you depends a lot on what else you are planning.

Ah thank you! What activities would require a half fare pass (e.g. Mannelich, waterfalls, should we go to another area nearby or is there plenty to do for 2 days in Wengen) - if we are in Wengen and want to venture and explore the area, that is likely our best form of transportation outside of walking?