You can play the game offline, but there are several things you need to do first: Install MW3 via disc or download. If you're using a disc, you'll be prompted to download a 70+GB patch.

Yes, you can play both the campaign mode and multiplayer mode in Call of Duty: Modern Warfare 3 offline. The campaign mode can be played in its entirety in offline mode, and a Private Multiplayer mode allows you to access all of the maps and modes present in Multiplayer.

You can download and play this content on the main PS5 console associated with your account (through the Console Sharing and Offline Play  setting) and on any other PS5 consoles when you login with your same account. For more information, please visit callofduty.