Hi ​@MillsQ,

Generally, your UK data and your roaming data are separate allowances, so using data in the UK won’t reduce what you can use abroad in the same billing month.
 

To double-check it for your specific plan, here are a couple of quick things you can do:

First, check your iD Mobile app or online account. it will usually show:

-UK data allowance
-Roaming allowance (if included)
-Any fair usage limits
 

Next, have a look at your plan details, because some older or specific plans may have different roaming rules depending on the destination (EU vs outside EU).
 

If you’re planning travel soon, it’s also worth switching on data roaming in your phone settings just before you go, so everything connects smoothly when you arrive.

Lamiya