Download [portable] Unreal Engine 4.27 Offline Installer Page

Create a folder named UE4_Prerequisites on your USB drive.

: The common way to "install offline" is to install the engine on a machine with internet access via the Launcher, then copy the entire installation folder (typically C:\Program Files\Epic Games\UE_4.27 ) to your offline machine. You can then run the UE4Editor.exe directly from the Engine\Binaries\Win64 subfolder. download unreal engine 4.27 offline installer