EE
International SIM
Lots of countries, but sadly several European countries not included.
O2
UK & International Bundles: Inclusive minutes to over 40 destinations. Just choose your bundle and top up the right amount to get your allowance. It will last for a month and renew automatically if there is enough credit.
Currently starts at 10£/month.
Vodafone
There are a few plans on offer for people who are on a pay monthly plan.
On Pay as you go there is an option to add a “Vodafone International” plan.
Add Vodafone International to your Pay as you go plan free, and make calls abroad from as little as 2p a minute. To get this Extra, simply text INTERNATIONAL to 2345 free from your Vodafone mobile. To opt out, you can text STOPINTERNATIONAL to 2345.
Lebara
A range of international plans are available.
Vectone
A range of international plans are available starting at £ 5 per month for 150 minutes.
Many mobile providers operate on a rolling contract basis.