The council has said it is important for householders to confirm who is registered to vote.
Electoral registration reminders have been sent to isles households to make sure voters can take part in the May 2021 Scottish parliamentary elections.
Each form contains a personal security code to enable online returns to be made, or householders can return the form using the pre-paid return envelope.
Isles depute electoral registration officer Ian Leslie said: “The right to vote at Scottish parliamentary and council elections now includes anyone aged 16 or over who lives in Scotland, and all resident foreign nationals who have leave to remain in the UK.
“To exercise your right to vote you must first be included in the register of electors. If your household hasn’t received a reminder, and you know that your household hasn’t yet registered, you can still do this online.”