To migrate your notes from Day One to Bear on macOS:

In Day One, select File → Export → JSON (zip) in the menu bar to export all your entries in one archive file.

In Bear, select File → Import From.. → Day One. An open panel showing a few options will appear. We suggest checking the option for involuntary tags escaping to avoid any unwanted tags being created. Then, select your Day One archive and click Import Notes.

Location info

Day One location information will be shown at the end of each resulting note in Bear as a titled link to Apple Maps.

Tags

All the imported DayOne entries will be tagged #dayone in Bear for easy access. Each entry tag will be converted to Bear’s #tags and shown at the bottom of the notes.