The United States may reach agreements with foreign countries to eliminate dual coverage and dual contributions (taxes) to social security systems for the same work. See Bilateral Social Security (Totalization) Agreements in chapter 2 under Social Security and Medicare Taxes. As a general rule, self-employed persons who are subject to dual taxation will only be covered by the social security system of the country where they reside. For more information on how any specific agreement affects self-employed persons, contact the United States Social Security Administration, as discussed under Bilateral Social Security (Totalization) Agreements in chapter 2.
If your self-employment earnings should be exempt from foreign social security tax and subject only to U.S. self-employment tax, you should request a certificate of coverage from the U.S. Social Security Administration, Office of International Programs. The certificate will establish your exemption from the foreign social security tax.
Send the request to the:
Social Security Administration
Office of International Programs
P.O. Box 17741
Baltimore, MD 21235-7741