Is roaming in Italy free with a UK or US SIM card, especially considering post-Brexit changes and EU regulations?

This depends heavily on your origin. For EU citizens, 'Roam Like at Home' generally applies in Italy. However, for UK travelers post-Brexit, most major UK carriers (like O2, Vodafone, Three) have unfortunately reintroduced daily roaming charges, typically ranging from £2-£6 per day. US carriers like AT&T or Verizon will also charge significant daily fees or offer expensive international plans. eSIMFlyer provides a transparent, cost-effective solution, ensuring you avoid unexpected roaming charges while enjoying Italy's wonders.