Only persons listed in a voters’ register may vote. Germans staying abroad who do not have a registered domicile in Germany are called Germans expatriate. They are not automatically entered into a voters’ register. If Germans expatriate wish to participate in Bundestag elections, they have to submit a written application for entry into the voters’ register before each election.
If you would like to be informed of the exact election date, you may register with the Federal Foreign Office to be on a ‘List of Germans’ and provide an e-mail address: https://www.auswaertiges-amt.de/de/-krisenvorsorgeliste/387662