Must foreigners participate in social security?

No, only foreigners who work in China need to participate in social security, and those who have no jobs don't.

According to Article 4 of the Interim Measures for Foreigners Employed in China to Participate in Social Insurance, if an employer recruits foreigners, it shall handle social insurance registration for them within 30 days from the date of obtaining the employment certificate. Foreigners sent by overseas employers to work in domestic work units shall be registered by domestic work units in accordance with the provisions of the preceding paragraph.

The institution that handles the employment permit for foreigners according to law shall inform the local social insurance agency of the relevant information of foreigners' employment in China in time. Social insurance agencies shall regularly inquire about foreigners' employment certificates from relevant institutions.

Extended Information "Interim Measures for Foreigners Employed in China to Participate in Social Insurance" Article 7 Foreigners who enjoy social insurance benefits on a monthly basis outside China shall provide the social insurance agency responsible for paying their benefits with a survival certificate issued by China's embassies and consulates abroad at least once a year, or a survival certificate notarized by the relevant institutions in the country of residence and certified by China's embassies and consulates abroad. Foreigners who legally enter the country can prove their living conditions at the social insurance agency on their own, and no longer provide the survival certificate stipulated in the preceding paragraph.

Article 8 A foreigner who participates in social insurance according to law may apply for mediation, arbitration or bring a lawsuit in case of a dispute with the employing unit or domestic work unit. If an employer or a domestic work unit infringes upon its social insurance rights and interests, foreigners may also request the social insurance administrative department or the social insurance premium collection agency to deal with it according to law.

People's Republic of China (PRC) government network-Interim Measures for foreigners employed in China to participate in social security