Basically, by virtue of the new agreement signed on December 24, 2020, the social insurance position for UK residents/nationals seafarers has remains the same as the provisions of Article 11.4 of EU Regulation 883/2004 which have been transposed into this Protocol, i.e. in accordance to Article SSC.10, para. 4 of the Protocol, they shall be subject to pay social security contributions in the Flag State.
Therefore, UK residents/nationals seafarers who will commence their employment on board a Maltese flagged vessel as from 1st January 2021, shall be subject to pay social security contributions in Malta by virtue of the Agreement reached between UK and the European Union.
With regards to UK nationals/resident seafarers who have been affiliated in the Maltese social security scheme before 31st December 2020, their social insurance position is treated under the Withdrawal Agreement which came in force on 1st February 2020. As provided by the Withdrawal Agreement if they continue with their activity on board the Maltese flagged vessel after 31st December 2020 they will continue to enjoy the benefits provided in EU Regulation 883/2004 provided there is no interruption in their situation. Accordingly, as from 1st January 2021 they are subject to continue paying social security contributions in Malta by virtue of Article 11.4 of EU Regulation 883/2004.
Therefore, just like before, UK crew members residing in the UK, shall claim unemployment benefit in the UK whenever they terminate the employment on board a Maltese flagged vessel. The contributions paid in Malta will still be taken into account by UK authorities for processing their claim of unemployment benefit.
Detailed and up-to-date information can be found here:
https://socialsecurity.gov.mt/en/international-relations/brexit-information/