The question around passport validity has been asked many times in the British in Austria Travel Facebook group and other groups; especially for someone with an Article 50 residence permit. Below is a summary, based on our current understanding, with official links.
Entering Austria – Article 50 Holder
The British Embassy in Vienna Living in Austria Guide has the following paragraph under their Passports and Travel Section.
“If you have rights under the Withdrawal AgreementWithdrawal Agreement The Withdrawal Agreement sets out the terms of the UK’s withdrawal from the EU and provides for a deal on citizens’ rights. It sets out a transition period which lasts until 31 December 2020. During this time you can continue to live, work and study in the EU broadly as you did before 31 January 2020. If you are resident in Austria at the end of the transition period, you will be covered by the Withdrawal Agreement, and your rights will be protected for as long as you remain resident in Austria. Any rights that are not covered by the Withdrawal Agreement will be the subject of future negotiations. https://www.gov.uk/government/publications/new-withdrawal-agreement-and-political-declaration , you can enter and exit Austria with a valid passport. You do not need any additional validity on the passport beyond the dates on which you are travelling.”
However, standard EU rules for Third Country Nationals are that a passport should have been issued in the last 10 years.
Another useful reference is the Schengen Border Guard Guide Definitions section (33) –
“Withdrawal Agreement beneficiaries have their previously exercised free movement rights, which they enjoyed as EU citizens, grandfathered only in their host State. With regard to movement in the Schengen States (other than their host State) they are to be treated as legally resident third-country nationals“
Summary: Make sure that your passport is less than 10 years old from the ISSUE DATE and you do not need any additional time on the passport for entering Austria. If you need to travel in an emergency and do not have a valid passport, you can apply for an Emergency Travel Document.
Standard EU Third Country National Rules apply if you are not a Withdrawal Agreement beneficiary.
Other EU Countries
The Withdrawal Agreement Rights are only in the host state (i.e Austria). If you enter via any other EU state, the special exemption does not apply and they can enforce standard Third Country National3rd country nationals Third country nationals are citizens of non-EU/EEA countries. Residency and naturalisation procedures for third country nationals are more complicated than for citizens of EU Member States or EEA signatory states. Rules.
Entering the UK
You can enter the UK on a valid British passport as per the end date.
The information above is based on the standard immigration rules, airlines can adapt these to a certain degree and apply their own conditions of carriage. Please check with your airline.