Please send us your suggestions for Austria and help others to get a reasonable SIM-card for their next trip!
Since 2019 Prepaid SIM cards need to be registered at purchase. See also: https://www.rtr.at/en/tk/Wertkartenregistrierung
Note: Austria has quite restricted opening hours for shops (compared with international standards). So it can be a problem to get a SIM card in the evening or at weekends.
Frequency bands are European standard. All providers offer LTE (upgrades).
International offers and reseller with international shipping: