Understanding SIM card and Wi-Fi requirements for iPhone 13 setup

The SIM (either a nanoSIM or eSIM) is provided by your mobile carrier and allows you to make mobile phone calls, SMS texts, and use the carrier’s mobile data network.

“Infrastructure WiFi” is effectively interchangeable with the “mobile data” described above; and depending on your mobile carrier might also carry “phone calls” and “SMS” as well. (commonly referred-to as “WiFi Calling”)

In almost ALL use cases you NEED the SIM, while the “Infrastructure WiFi” is “VERY desirable to have when it’s available.”

Your iPhone additionally has the ability to serve as a WiFi hotspot allowing other devices to connect to your carrier’s mobile data via the WiFi in your phone; although the exact characteristics of this feature are entirely dependent on the service plan to which you’re subscribed from your mobile carrier.

Clear as mud ?

donaldbr wrote:

1st time iOS user, iPhone 13, I an have android phone i'm moving from, my MacBook connected to wifi via android hot spot

It is not clear to me if I need both a SIM card & wi fi separately? when I put the SIM card into the iPhone13 I seem to need a separate wi-fi connection?

When you are using your phone as a Hotspot, it is connecting to the internet via cellular. Your MacBook is connecting to the iPhone Hotspot just like it would any other WiFi router. So, yes, you have to have WiFi enabled on your iPhone, but no, there doesn't have to be a separate WiFi internet connection. If there were a separate WiFi connection, you could just connect your Mac to that.