Anyone seeking to run as a candidate can announce their intention at any time. This is an individual choice made by the leadership prospect and their campaign - the party does not determine dates for individual campaign announcements.
However, applications from all individuals planning to run in the contest must be received by the leadership contest committee (the administrative body of the leadership contest) by July 27, 2020.
After receiving an application, the committee reviews the applicant’s eligibility to run as a candidate and will approve or decline the application. The party will then list the new official candidate on the leadership contest website.
With the deadline to submit applications on July 27, we expect all last-minute submissions will have been approved or declined by August 17, 2020. At that time, the party will publish an official, full list of candidates seeking the leadership of the party.