Draft response:

Hi Vicky,

there is currently no generic/free-form CSV import format in Diarium. The CSV-based workaround is to convert your data into the format expected by the Daylio migration and then select Migrate from other app > Daylio.

Related discussions:

Is it possible to import entries from Wordpress?
importing files DIY
Share Structured Data Into Diarium
Import from text file
Import CSV Zeilenumbruch
Import CSV from Universum app
Incomplete migration of Daylio-CSV File
The import of Daylio-CSV removes all line breaks

For a simple text-only import, the Daylio CSV columns Diarium reads are:

full_date,date,weekday,time,mood,activities,note_title,note
2026-06-07,7 June,Sunday,14:30,good,"tag1|tag2","Entry title","Entry text"

The important columns are full_date, time, note_title, note, activities, and mood.

For a WordPress conversion, especially if you later want to preserve images/attachments more cleanly, converting to a supported journal export format such as Day One JSON/ZIP may be the better target than CSV.