The following can apply to vote by post in Senedd elections by submitting an application to the Electoral Registration Officer (ERO) at their local authority:
a person aged 16 or over who is registered to vote
a person aged 16 or over who has applied to be registered to vote
a person who has been appointed to vote as a proxy on behalf of someone else
The application must be received by the ERO by 5pm 11 working days before the poll.1
The ERO has no discretion to extend the deadline for whatever reason.