Are roaming charges incurred in Austria with a UK or US SIM card?

For UK and US SIM card holders, roaming in Austria typically incurs charges. While Austria is an EU member state, the 'Roam Like at Home' (RLAH) regulation applies exclusively to EU citizens using an EU-issued SIM. Post-Brexit, most UK carriers, including Vodafone UK and O2 UK, have re-introduced daily roaming fees (e.g., £2-£6). US carriers such as AT&T, Verizon, and T-Mobile US generally apply international daily passes or per-MB rates, which can be costly. CoreESIM offers a predictable alternative.