How To Purchase Half Fare Card With SBB App

You can't. From the SBB website FAQ for the 30-day Half Fare Card.

If you have ordered the Swiss Travel Pass, Swiss Travel Pass Flex or Swiss Half Fare Card, please note that this is a tourist pass and cannot be linked to the SBB app. There is a similar product called SwissPass, which is only valid for Swiss nationals and is not part of the Swiss Travel System offer.

What you should do is buy it on the website. But make an account first. Then you will see the pass later in the SBB app.
But it is not needed to link the pass to your app to buy half price tickets, as you can just select the half price reduction even without having the pass. It is on the train itself, during the ticket inspection, that you must be able to show the half fare card, on way or another (a printout is sufficient) when you show a half price ticket.

More details here: https://community.sbb.ch/blog/35831-swiss-half-fare-card-how-to-buy-and-details

Thank you Sam and WengeK.

Don't waste your time. After about seven hours two of us gave up and will buy it in the train station. Unless you are a Swiss
national, the website will not work for you. It's awful.

Swiss residents cannot buy the Swiss Half Fare Card or the Swiss Travel Pass. So if the website would only work for the Swiss it would be pretty useless.

Lots of people manage to sucessfully by these passes on the website. What went wrong in your case?

Generally, I have found that SBB requires 2-factor authentication for online credit card purchases. If your US credit card does not support 2-factor authentication, you are pretty much out of luck.

I’ve had no trouble using my Chase VISA to purchase passes online. And I believe my SBB app is connected to my apple pay.

Switzerland does not like my credit cards so if tap and pay doesn’t work, I have to insert the card and then sign the receipt. This was as of June 2024.