No, roaming in Greece with your UK (O2, EE, Vodafone) or US SIM card is generally not free and can be very expensive.
This is a common roaming trap for travelers. While your UK or US SIM card will technically "work" in Greece, allowing you to make calls and use data, your home network will almost certainly charge significant fees. Post-Brexit, most UK carriers like O2, EE, and Vodafone have reintroduced daily roaming charges for using your phone in Greece. Similarly, US and Canadian providers often charge high "Day Pass" fees.
- **UK Networks (O2, EE, Vodafone):** Expect daily roaming fees, typically £2-£6 per day.
- **US & Canadian Networks (e.g., AT&T, Verizon):** Be prepared for expensive "Day Pass" charges, often $10-$14 daily.
- **The Roaming Trap:** These daily fees apply to your data, calls, and texts, quickly accumulating to high costs.
These daily charges quickly add up, making data roaming in Greece far more expensive than expected. A popular and significantly cheaper alternative for many travelers is to use a prepaid eSIM, which offers a one-time fee for your data needs without recurring daily charges.