International cooperation allows partnerships to address global challenges and to extend their reach beyond the European Union. National funding agencies from third countries may join joint transnational calls, and entities from third countries can participate as associated partners, observers or beneficiaries subject to national rules. Partnerships may also engage in strategic collaboration with international organisations. International participation must respect Horizon Europe rules on eligibility and strategic autonomy, with safeguards to protect intellectual property and ensure reciprocity. Examples include Biodiversa+ involving Brazil, Morocco and other countries in its calls and OHAMR collaborating with the World Health Organisation.