Detailed information can be found on the German page.
Military service for the Swiss or Swiss with dual nationality
Swiss who are citizens of another state in which they have performed military service may not in principle be recruited into the Swiss Armed Forces.
Swiss Abroad who volunteer for the Swiss recruit school will be called up only if they meet the following conditions:
do not exceed the age limit for recruitment (end of 24th year);
are not citizens of the country of residence (subject to any bilateral agreements on military service for dual nationals which may exist);
have sufficient command of one of the Swiss official languages;
have never been convicted of a serious offence;
successfully complete a personal security check. In accordance with the Federal Act of 21 March 1997 on Measures to Safeguard Internal Security (SR 120), the Federal Act on the Armed Forces and Federal Administration (SR 510.10) and the Ordinance of 4 March 2011 on Personnel Security Screening (SR 120.4) conscripts must submit to a security check for personnel at the time of recruitment, if so required by their function. They will be examined at the same time to determine if there are reasons for not supplying them with a personal weapon. The original of your criminal records extract, issued by your country of domicile and legalised or with the appropriate apostille, must be submitted to the specialised service responsible for the personal security check in Berne. The security checks can be ordered only by the relevant services, namely the Armed Forces Personnel (Pers A) of the Training Command. The application form and the criminal records extract are to be handed to this authority.
If you feel that you fulfil the above mentioned conditions and would like to attend the Swiss recruit school, you should report to the Armed Forces Personnel (Pers A) of the Training Command for additional information and registration.
Swiss Armed Forces: Swiss Abroad (de, fr, it)
Swiss Armed Forces: Dual nationals (de, fr, it)