Tumblr does not offer any sort of automated tool for exporting or importing content. To load your old content into a new blog, you will have to tackle each post one by one. While this is fine for new blogs or blogs that do not have a lot content, it becomes tedious for older blogs that update more frequently. Reblogging content is the faster way to move content to a new blog. You can copy and paste individual posts if you do not want to reblog them. Bear in mind: moving content may be unnecessary if you just want to change blog settings.

Reblogging Old Content

The easiest way to transfer posts from one of your blogs to another is to reblog it. This will show the content as originating on your first Tumblr account, and displays the old account name. Reblogging goes quickly and allows you to modify content before posting it to your new blog. To reblog a post, open the post in a browser window, and click reblog in the upper right corner. You can open your Tumblr archive at username.tumblr.com/archive to navigate your posts chronologically.

Copy/Pasting Old Tumblr Content

If you do not want to reblog your old posts, the other option is to manually copy and paste the entries from the old blog into new posts. You may need to use an external text editor, such as Notepad or Word, to save content. The unofficial app Tumble-log Backup Jammy allows you to save exported content, if you want to download then delete the old blog posts. (Link in Resources.) Tumblr does not have an official tool to export your posts.

Backdating New Posts

If you want the new posts to have the original dates, backdate the post when you reblog it, or edit it after it has been posted. Click the gear icon in the upper right corner when reblogging/editing the post, and enter the past date in the "Post Date." Enter the date and time in a human-readable way, e.g. "January 12, 8:00AM." The post will go to the correct place in your timeline, and show the backdated time when people view the post.

Changing Blog Settings

Moving your Tumblr blog content is tedious, especially when you consider that ever aspect of your Tumblr blog can be changed. Tumblr allows you to change your username (and thus, URL) at any time, and use a new theme if you want a new look. You can unfollow any users you no longer want to see content from, and even change the email address associated with your account. If you only want to change the style of your blog, consider these changes instead of the tedious process of moving your content.

Disclaimer

This article refers to settings and options that were available in January 2014; availability and processes may change with future updates to the Tumblr website.