I have topped up a Vodafone UK SIM about three weeks ago using a German VISA on https://topup.vodafone.co.uk/topup/ There was no problem.

Please note that the EU regulation 2018/302 (https://eur-lex.europa.eu/legal-cont...8R0302&from=EN) which enters into force in December this year, dictates non-discrimination of different means of payment. So all credit cards issued in the EU will have to be treated in the same way and cannot be rejected.

The same EU regulation also prohibits any geo blocking of online pages which are used for administration of a service or purchase and payment except for copyright protected works. Anybody within the EU will have to be able to buy a topup with the same conditions. Also the online stores like AppStore and PlayStore wil have to offer all the apps except those for access to copyright protected works to everybody within the EU.

So many operators are already preparing now and start accepting all EU credit cards and are removing geo blocking. As always, there will certainly be some which will not comply with the regulation. And if Brexit happens in March, the things might change for the UK.

But with Three I can use up to 12 GB in 70 Countrys.

And I can call for only 3 penny per Minute.