We wanted to get a UK or European SIM card in London (flying into Heathrow). We'll be spending a week in London and another week in Paris and don't want to be charged extra for EU roaming in France using a UK SIM card. I heard many companies used to allow free EU Roaming but Brexit changed that. Any recommendations for good SIM card packages to get in London that would also work in Paris?
I don't know anymore - the carrier policies are constantly evolving. Some UK mobile operators are starting to charge roaming surcharges if roaming in the EU.
Lots of info/details here:
https://prepaid-data-sim-card.fandom.com/wiki/United_Kingdom
Currently EE still allows EU roaming on its pay as you go plans. Check under the good to know section for the list of countries. They have shops throughout London. I went to the one near Covent Garden. Reasonable price vs many US carriers.
Lebara uk, Giffgaff and Lyca uk still offer eu roaming. There might be a few more.
They all offer 5g in UK. Lebara offers 5g while roaming sometimes, such as in Germany.
The other carrier might offer the same, but I haven't used them.