Thanks, that's good to know.
The post office in the town I'm going to has a Post Partner, so I'm guessing some kind of outsourced company running a post office for a small town.
I'm almost tempted to try to order the Welcome kit online and have it sent to the hotel where I'll be staying.
I want to add a 15 Euro package for 10 GB of data but I may have to set up an account on the A1 website to do it. I can't find a way to text to activate a specific package. They do have an iOS app. but it's not available on the US app. store.