Hi @Ms1688.
Thank you for your post.
Roaming in both Greece and Spain is included as part of your standard allowance, so your phone should work as normal once you arrive without needing to change any settings.
To avoid any additional charges for usage outside of your plan, we'd suggest setting your bill cap to £0 before you travel.
For more information on roaming, you can also check out our dedicated page here: https://www.idmobile.co.uk/help-and-support/eu-roaming
Have a great trip, and let us know if you have any other questions before you head off!
Thanks,
Marquerita
The iD Mobile Team