I'm in the process of switching my UK mobile phone provider from Three to SMARTY. I'm on a Pay As You Go (PAYG) tariff. I had £9.39 of credit left on my account. Annoyingly, you can't get a refund for PAYG credit. I don't want this money to go to waste.
I could donate it to charity via a text to donate number, but I wanted to see if I could find another option.
How to top up your Apple ID balance with mobile credit
I discovered that I can add my mobile phone as a payment option on my iPhone and transfer most of my PAYG credit to my Apple ID balance. To do this, go to Settings, click on your name at the top to access your Apple ID. Then click "Payment & Shipping" and "Add Payment Method". You will then see this:
Select "Mobile Phone" and "Use This Mobile Number". This option is available in the UK for customers of EE, O2 and Three (via Three Pay).
I then removed any other payment methods so that I could be sure any payment I made would be taken off my mobile phone credit. (I added my other payment methods back later.)
Then click back to your Apple ID settings and select "Media & Purchases" and "View Account". Then click "Add Funds to Apple ID". I was able to add £8.80 of my £9.39 credit, leaving only £0.59 behind. You have to transfer whole pounds and it seemed like I had to leave at least £0.50 credit on my Three account. It's actually quite useful to have a small amount of credit left just in case I need it while I'm waiting for my mobile number to be transferred to my new network.
I'll use my Apple ID balance to pay for iCloud storage, but it could also pay for any subscriptions, such as Strava or Bear Pro.
Why I'm switching from Three to SMARTY
I'm switching to SMARTY because, in lockdown, I barely use my 4 GB of data, which I get from a monthly £10 add-on. Ideally, I'd use giffgaff, but they still don't support wifi calling, which is essential in my highly insulated eco house, which destroys mobile reception indoors. On SMARTY, I expect to spend £6 a month, and could even be refunded up to £1 if I don't use the 1 GB data allowance on the data discount plan. Any additional data costs £1 per GB, so I won't be paying for data that I don't use and can't roll over. I also found Three annoying because my older SIM card wouldn't let me set up auto-renewing payments each month.
Switch to SMARTY and get a free month
If you think you're spending too much on your mobile phone bill and want to try SMARTY yourself, you can get a free month if you sign up with this referral link. You'll be treating me to a free month, too. (Thanks!)