Is international roaming free in non-EU or non-domestic zones with my US, UK, or EU SIM card?

No, international roaming in countries outside your home region (e.g., US, UK, EU domestic zones) is almost never free and can be exceptionally expensive. Carriers like AT&T, Verizon, T-Mobile in the US, or Vodafone UK and O2 in the UK, typically impose high 'Rest of World' daily charges or per-MB rates. WestESIM offers a transparent, cost-effective alternative, providing dedicated data plans that eliminate bill shock and ensure reliable, high-speed connectivity.