​@catandrews1987  Mobile devices don't come locked to a network they are sim free in the UK. Unless your currently using an Esim and you requested a physical sim card which will have your current number with the upgrade it won't come with a sim card.

You be able to get a sim with a new number for use in the new iPhone there are 30 day, 1 year and 2 year sim only Contract with IDMobile. 

Joe

Hi ​@catandrews1987 ,

I completely agree with what ​@JoeKing  mentioned , all iD Mobile phones are SIM-free in the UK, so they’re not locked to our network. This means your new iPhone 16 will accept any SIM, whether it’s from us or another provider.

If you requested a physical SIM with your upgrade, it will have your current number. Otherwise, if you’re using an eSIM, you can continue with that on your iPhone 15. For your son’s iPhone 16, you can easily get a SIM-only plan with us – we offer 30-day, 12-month, and 24-month options.
This setup should work perfectly for what you’re planning, and it’s definitely easier than it sounds.

Lamiya

Thank you so much for the reply last night!! 
 
it’s made me feel super old thinking that phones are still locked to a network! 🫣 I can’t remember which sim I chose at upgrade, think I stayed Old school and asked for a proper SIM card.. again… Old. Haha. thanks again feel more reassured! 

This is great, thanks so much and i was looking at the rolling monthly sim last night with ID Mobile seems quite reasonable too! Will wait for the phone to arrive (can’t quite remember which sim option I chose) and go from there, still got lots of time before Xmas to figure it out! My 10 year old will be so so happy! Thanks again ☺️