The earliest date you can officially become a candidate is the date of dissolution of the Senedd. You will officially become a candidate on this day if on or before this date you or others have already declared you as a candidate.1
If, after this date, you or others declare that you will be a candidate at the election, you will become a candidate on the date such a declaration is made, or on the date that your nomination papers are submitted, whichever is earlier.2
You can start campaigning before you officially become a candidate. More information is set out in our guidance on campaigning.