sim card doesn't fit iPhone 12

Try turning it over - I thought this as well but it goes in gold side up

The physical sim card in iPhone X is the exact same size as the sim in iPhone 12. They are both nano sized sim cards. The card is held in a tray in the phone. Perhaps the tray is different size, but the sim card itself is the same.

I would recommend you get a new sim from your carrier anyway to ensure it is correctly provisioned for 5G service.

It certainly should. The sim card is the same size in both phones. Did you remove the card from the sim tray, then remove the sim tray from the iPhone 12, remove that card and replace it with the sim card from your iPhone X?

i had the right one but tried to get it in with the gold side down like all the previous versions. I thought I went through all of the possible orientations and felt kind of stupid when I discovered I apparently had missed the right one 😀

It's not the same card its smaller on the 12... the ********

Thanks!

So yea I had to get a new one form my carrier I had an older sim card.