The transition period ended at 11pm on December 31st 2020. This means German nationals can no longer apply for British citizenship without the risk of losing their German citizenship.

Germans who wish to obtain citizenship of a non-EU country have to apply for a Beibehaltungsgenehmigung (permit to retain German citizenship) to avoid losing their German citizenship. If you are German, you need to make sure you apply for this before applying to become British.
The information below details the arrangement that were in place during the transition period.

Germany only allows dual citizenship with other EU countries.

You need to inform the German authorities after you get your ceremony and Naturalisation Certificate

See: German nationals after naturalisation - UKCEN Citizenship and Residence for European Nationals and their families

It is not possible to obtain a Beibehaltungsgenehmigung (BBG) for an EU country - this means that Germans who applied for UK citizenship before Brexit cannot obtain a BBG because the UK was still part of the EU, but they would have risked losing their German citizenship if they only finish the process after Brexit. In order to avoid this problem, new legislation was passed in Germany.

Brexit Transition Act


Germans need to submit their UK citizenship application before the end of the TRANSITION PERIOD (but not finish the process) in order to retain their German citizenship.

The relevant date is when the application is submitted online and payment is made.

Make sure you keep your submission confirmation email and payment receipts to be able to prove to the German authorities, that the application was submitted before the end of the year.

The date of the UKVCAS appointment is not relevant. There's no need to have the appointment before the end of the year.

The same applies to UK citizens applying for German citizenship.

Useful links and info (in German)

Brexit transition act:
No deal legislation:
FAQs published by German embassy:
  • Question 15: brief summary of deal and no deal legislation
  • Question 16: how to proof submission date of citizenship application
  • Question 17: info on Beibehaltungsgenehmigung

With special thanks to BabelFish