Does anyone have any insight on which SIM cards or plans are best used visiting England & Scotland. I'm not looking for minutes for calls, only data. Fido & Bell have a Roam option you can have, but I'd have to significantly upgrade my existing plan and it doesn't seem worth it. I use roam mobility in the USA and it's fantastic, if anyone knows of a similar company for the UK, please let me know.

try roam mobility or Globalgig. It looks like Global gig still have the free 100mb data option so if you get them to send you multiple sim cards (for another family member) you could essentially get free data but their rates aren't expensive either. Last time I had to email them directly to get the Sim Cards which are free.

There r kiosks operated by various companies here and there, especially in major transportation hubs like the tube, railway stations, airport. They sell Sim cards with different sorts of plans. Can go online to research best option. At Heathrow there's a company kiosk just outside international arrivals which I used. Very expensive, but easy. Was later told I could buy a Sim card for under 5 at stores. Have to put it in yourself.

A company called ee has a 4gb sim for 15 pounds, but they only take UK credit cards & billing addresses. Lucky for me I have someone who can buy it and mail it to me....

go to tesco supermarket, if you have an unlocked phone, and buy a pay as you go sim card for 15 pounds for the month it has free calls text and data, do it every time i'm in UK works good and cheap, but you must have an unlocked phone

Carphonewarehouse (which is everywhere) offers all companies and you can compare companies, etc. I got a 30 day ee sim card for 10 pounds. I think it had 5 gb data. Also unlimited texting which came in very handy, and 100 minutes phone which I didn't use much at all.

Wow, thanks for all the quick, awesome responses, what a great community!!

Really good to know!

Recommend against: We used OneSIM and had trouble using their voice & data service. As well, you buy minutes and data ahead of time, but all of it expires after a time ... even if you cannot access the service. No refund policy too.
I found that in Ireland & the UK, buying a local SIM chip and/or phone worked as well as anything else you could get over here in Canada. Good luck!

giffgaff is 100% cheapest. They're a full online company so pass on the savings that way. You have to preorder a sim card online FYI. Check them out online.