For Jetpack enabled sites, you can migrate your users who have subscribed to your WordPress.com site either by email or via the WordPress.com Reader to your Jetpack-connected self-hosted WordPress site. To migrate subscribers on plugin-enabled WordPress.com sites, please contact support.
Note: Both the WordPress.com site that has the followers and the Jetpack site that will be receiving the followers must be using the same WordPress.com user account. This WordPress.com account needs to be the owner of the WordPress.com site. Having an administrator role on the WordPress.com site is not enough.
In other words, the owner of the WordPress.com site needs to connect Jetpack to their account and initiate the transfer.
Important: This tool does not migrate “likes”.
In this document, we’ll walk you through the steps of how to transfer your WordPress.com followers and email subscribers to your Jetpack-connected self-hosted WordPress site.
How to transfer your followers.
Log into your WordPress.com user account and go to your My Sites page.

Next, click “Switch Site” on the Site Picker, and select your Jetpack-connected self-hosted site from your site list.

After selecting your self-hosted domain, go to Settings > Discussion. Scroll down and click on Migrate followers from another site on the bottom:

In the “Move Followers From A WordPress.com Site” area, select your WordPress.com site that has the followers. Then, click the “Migrate” button as shown below.

Once you click migrate, you will see a pop up window wanting you to confirm that you want the followers transferred:

Click “Ok” to proceed with the transfer. You will see another notice at the top of the screen that your follower migration has been queued:

You will receive an initial email to the email address associated with the WordPress.com account stating that the transfer has been started (#2 in below screenshot) and that the transfer has been completed (#1 below):

Please note it may take up to a day for the follower counts in your stats in your Dashboard to accurately reflect the transfer.
Keep in mind that while your email subscribers will continue to receive email notifications of new posts as before, WordPress.com followers will only see new posts in the Reader. They will not receive email updates unless they subscribe to receive those on your new site. You might want to post a notice on your old site about your upcoming move to keep your readers informed.
Troubleshooting migrations
Can I use this tool to move followers from one WordPress.com site to another WordPress.com site?
No, this tool is only available for migrating WordPress.com site’s followers to a Jetpack-connected self-hosted WordPress site.
If you need to migrate your followers from one WordPress.com site to another, please contact WordPress.com support.
To migrate followers from Jetpack to WordPress.com or from one Jetpack site to another, please contact us with the URLs of the sites you’re moving from and to.
Still need help?
Please contact support directly. We’re happy to lend a hand and answer any other questions that you may have.