To find out details of O2 charges and top up when abroad use the following link
Using your Mobile phone abroad can be a very costly experience.
You can be charged twice for any call to the UK.
Many mobile phone users do not know that by accessing their voicemail from abroad they are also likely to be charged twice.
Here are the T-Mobile International options but please note they are all only valid for calls from the UK to other countries, calls to the UK are charged at the normal tariff e.g. Canada 55p/min
To find out details of O2 charges and top up when abroad use the following link – O2 ABROAD
My Suggestion to save yourself a fortune
1. Check out the cost of calls from the country your are visiting to the UK
2. When you arrive at your destination buy a Pay-as-you-go Mobile phone
3. Call home, or text your number
Obviously if needed also buy one for your better half.
This method will probably work out a fraction of the cost of using your normal mobile