I live in Canada and work at my company's Canadian office. My company also has an office in the USA which I have already worked at and have a valid TN visa. My question is I want to get a SSN for future usages if I go work back in my company in the USA, can I go to the nearest US city and enter in with a tourist visa and apply for an SSN or do I need to enter in with my TN visa even though I will not be working I just want to apply for an SSN and then leave?
According to Original Card for a Noncitizen Adult (click on "Noncitizen" on the left):
In general, only noncitizens who have permission to work from the Department of Homeland Security (DHS) can apply for a Social Security number.
To prove your U.S. immigration status, you must show us your current U.S. immigration document, such as:
- Form I-551 (Lawful Permanent Resident Card, Machine Readable Immigrant Visa) with your unexpired foreign passport;
- I-766 (Employment Authorization Document, EAD, work permit); or
- I-94 (Arrival/Departure Record) or admission stamp in the unexpired foreign passport.
It follows from the above that you would be unlikely to be able to apply for an SSN after having entered the US as a tourist.
In my experience, US border agents do not take a favourable view toward Canadians who wish to enter the US with TN status and intend turn around and leave again. I would suggest applying for an SSN at the SSA office nearest your place of employment, the next time you need to work at your company's US office.