Viewing Space Safety, Security and Sustainability as highly topical fields and aiming to promote an informed debate about the future of the United Kingdom (UK)’s participation in the European space sector after its withdrawal from the European Union (EU), this Article discusses the UK’s beneficial options to participate in core EU and European Space Agency (ESA) engagements concerning Space Safety, Security and Sustainability as of December 2021. It finds that, post-withdrawal, UK participation options in EU Space Safety and Security engagements are now much more restricted. The UK still has various notable participation options in ESA Space Safety engagements. The Article points out several developments that might restrict UK participation in ESA and EU Space Safety and Security engagements, and provides various recommendations to the UK in this regard.