on 28-10-2018 20:00
Have a look here https://www.o2.co.uk/shop/international/using-phone-abroad
Please note this forum is not Customer Services and forum members are customers just like you, this means we don't have access to your account details.
If you have an account specific question, please use the contact methods on this page https://www.o2.co.uk/contactus
on 28-10-2018 20:15
Your phone should be set up to work when abroad automatically if you purchased directly with O2, but, be aware of the costs please.
OnePlus 6 (O2 & Sfr), Z3 Tablet (Three UK), iPhone 8+ (EE)
on 28-10-2018 21:54
You would be better off contacting customer services in the link above to make sure there are no roaming bars on your account.
A number of people recently have complained about this whilst abroad. It shouldn't be an issue... though it is happening more frequently for some strange reason.