Should Data Roaming Be On or Off Abroad?
This is one of the most-searched questions about international travel and the answer is nuanced — it depends on what plan you are using. Here's the complete explanation.
The short answer
**If you have a travel eSIM or local SIM:** Data roaming must be ON for the eSIM/local SIM line.
**If you are relying on your home carrier abroad:** Data roaming being ON will use your home carrier's international rates, which can be extremely expensive. Turn it OFF unless you have an international data plan from your home carrier.
Most confusion comes from mixing these two cases.
What data roaming actually does
Data roaming allows your phone to use a carrier network that is different from your home carrier. When you are in a foreign country, every network is technically a "roaming" network — even a local SIM card purchased in that country counts as roaming to your phone's software.
Disabling data roaming prevents any mobile data from flowing through that SIM line. Signal bars may still show, but no data traffic passes. This is a device-level setting that overrides carrier configuration.