You'll find pretty much all of the most commonly recognised countries in the EU, in our Euro Zone, but with additions like the Isle of Man.
See the full list of EZ countries, here: http://guides.plan.com/pro-europe/
To configure a Spend Control¹ for roaming usage, from the dashboard of your my.plan account, go to:
CONTROLS > SPEND CONTROLS > DATA/CALLS/TEXTS > UK/EU or ROAMING > [select user] > SET UP
To configure an Ofcom Total Spending Cap² , from the dashboard of your my.plan account, go to:
CONTROLS > SPEND CONTROLS > OFTOM TOTAL SPEND CAP > [select user] > SET UP
¹available to Gold & Platinum account users and Essential account users via an upgrade.
²available to new and renewing customers from 1st October 2018