Stolen iPhone 11 with no SIM still moving in Find My

It has no sim, so it probable has no internet connection

You might be surprised to learn that your phone can report on its location using Find My.....even if the phone has been powered off. This assumes that there is still some charge left on the battery of course and that there is at least another iPhone in close proximity to your phone to forward the intermittent Bluetooth signal that your phone is sending out.

If the phone cannot connect using cellular, it can still connect using Wi-Fi and also via Bluetooth.

I have marked is Lost but is still pending.

The phone will not be able to confirm that it is in Lost Mode until it has a good solid Internet connection. That would mean that the phone must be connected to Wi-Fi, since it cannot connect using cellular.

How do i make sure the theft wont get access to my data/photos if he decides to connect it to a personal computer?

You did set up a Passcode on your phone, correct? There is no way that anyone could ever guess your passcode in less than 10 tries before the phone locks out and will not even allow any more log on attempts. It does not matter whether the phone is connected to a computer or not.

Please read through the Apple Support document below for more information:

Find your lost iPhone or iPad - Apple Support

Unfortunately, the chances that a stolen phone can ever be recovered are just a tiny fraction above zero, so you have to realistic about things here.

The device will still update its location as long as there is another iPhone within bluetooth range that does have an internet connection. The thief cannot get access to your phone as long as it was locked with the PIN. They won't be able to access it using a computer and the Activation Lock will prevent anyone else from using it. I would expect the Lost command should still go through using the same connection to the other iPhone that is transmitting its location, but I cannot be positive as that is not detailed in any Support Article.

I would expect the Lost command should still go through using the same connection to the other iPhone that is transmitting its location

It won't.....in the limited tests that I've done. Remember, the stolen phone sends out a very brief intermittent Bluetooth signal to try to report on it's location. Not the same as a normal Internet connection via cellular or Wi-Fi.

As far as I can tell......the stolen phone is not really sending out information about its location. It is the nearby phone that picks up the Bluetooth signal and reports the location of the nearby phone, which is in close proximity to the stolen phone.

With no SIM Card and no Wi-Fi connection, the stolen phone is not connected to the Internet, so Location Services is not working at the time.

Even with passcode, the theft will still be able to access photos if he connects it to a personal computer right?

If the thief knows your passcode, you must have given it to them, since there is no way that anyone could ever guess your correct passcode in the very limited number of tries that are allowed.

It does not matter if the thief connects your phone to a computer. If the thief does not know your passcode, they can't get into the phone.....no matter what they do.

You did have a passcode on the phone......correct?

If you did.....you need to stop worrying.

Do i need to erase the phone through Find My?

Yes, if you are still concerned that someone can get into your phone.....even though they can't.

But, you won't be able to erase the phone as long as the phone continues to report that Lost Mode is "Pending".

If you decide to send a request to erase the phone.....that action will also be "Pending" as long as Lost Mode is pending.