Replacement SIM card

[FrankMurphy]

Hi,

I am having problems with internet signal. I have had several hand me down phones from my wife, the one I’m currently using is an iPhone 12 Pro Max. 
the SIM card I’m using is years old from previous phones. 
I can rarely get decent internet use. Even when my phone displays 3G and 4G I often don’t get any internet and regularly have to put my phone in and out of flight mode to be able to use it. 
I’ve been told by friends that I need a new SIM card. Is this likely?

cheers

[pgn · Accepted solution]

Sounds like you might, @FrankMurphy - quickest way is to take phone, SIM and some photo ID with you to the nearest O2 Shop or store. Good luck!