If you live abroad and will shortly reach statutory retirement age, it is your personal responsibility to make the appropriate administrative arrangements for your retirement.
Preparation for retirement - resident abroad
Generally speaking, you should submit your pension claim no later than three months prior to reaching the statutory retirement age, as this will give your compensation office sufficient time to gather the information they need to calculate your pension.
The Swiss Compensation Office website has detailed information on Old-Age and Survivors Insurance.
Switzerland has entered into social security agreements and conventions with various countries. The basic objectives of these accords are: equal treatment of nationals of the other contracting country; determination of the applicable legislation; and the international portability of social security benefits.
Normally, pension claims in countries with which Switzerland has concluded a social security agreement or convention must be submitted to the liaison office of the social security provider in the applicant’s country of residence. The liaison office will refer claimants to the appropriate service.
CCO: Request for an old-age pension
Federal Social Insurance Office FSIO: International social insurance
Detailed information can be found on the German page.