Knowledge Base Help & Documentation:
What should I do to migrate my comments to Joomla CMS?
While moving your comments from your Existing CMS to Joomla, there is the need to install JComments Joomla extension before the migration. In this way you will ensure that all your current website comments will be migrated to your New Joomla website.
After installing and activating the JComments extension on your new Joomla website, select the entity “Comment” in the Migration Wizard and proceed with the migration.