Google’s John Mueller said on Twitter that when your root domain is moved over to mobile-first indexing, that means all your subdomains move with it. I suspect that this is the case for (a) sub-domains that are not like hosted WordPress sites that use subdomains for their URLs and (b) that the whole domain, including all the subdomains are ready for mobile-first indexing.

So when Google moves over to mobile-first indexing, that if it had, and other subdomains, all of them also would move with it. I would also clarify that Google probably won’t move the domain to mobile-first indexing if the subdomains were not ready.

Here are the tweets:

Forum discussion at Twitter.

This post was pre-written and scheduled to be posted today, I am currently offline.

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