Patching with no internet - Linux 2

Hello all.

I couldn't find solid information on the AWS site, but I am making an assumption I want clarified on please.

I am deploying some Linux 2 Instances and understand they can be patched using Patch Manager. It appears that the standard repos are amazon based and accessible regardless of whether the instance has access to internet. Is this correct, or does the instance need access to internet to download patches, like any other machine ?

Many thanks.