Sep 1, 2015 - 6:32 PM
Hi LValentine, thanks for joining us!
If you get Swiss Half Fare Cards for the adults, your tickets will be 50% discounted (saving about CHF 100 per person on the Jungfraujoch fare). If you also plan to do other trips by cable car or boat you get a discount on that too. You'll get a free Swiss Family Card which allows your daughter to travel along for free everywhere. Please see here for all the details and retailers: myswissalps.com/ swisshalffarecard.
The Swiss Family Card only applies if a parent travels along. Your daughters friends travel at half the adult fare. You can also buy them a 1-day travel pass for CHF 16. That allows them to travel along for free, but not to mountain peaks. Most of those are 50% discounted. In case of the Jungfraujoch they travel for free to Wengen and Grindelwald, and the rest of the trip is 50% discounted (about CHF 85 per return ticket).
You can start your day trip from the rail station Interlaken Ost. That allows you to do the round trip via Grindelwald and Wengen.
Here are some additional resources: