Can I use an old sim with no service in an iPhone to use it for my wifi?

[Itsnotahickey]

I'm upgrading and keeping my old phone to watch stuff on at home using wifi. When I transfer my number to my new sim, and my old sim loses service, can I keep that dead sim in my old phone or do I need to get a PAYG SIM card for it to not die?

You shouldn't need a SIM card in it if you're just using WiFi.

Ah that's great! Thank you!

I'm doing the exact same thing! So yes, you can.

As others have said, just use it without a SIM, it’s essentially a tiny tablet.