USCIS application procedures:
Diplomatic Visas

The type of visa required by a diplomat or other government official depends upon his or her reason for entering the United States.

To qualify for an A-1 or A-2 visa, the individual concerned must be traveling to the United States on behalf of his or her national government to engage solely in official activities for that government. The fact that there may be government interest or control in a given organization is not in itself the defining factor in determining whether or not the applicant qualifies for an A visa; the particular duties or services to be performed must also be of an inherently governmental character or nature.

Local government officials representing their state, province, borough, or other local political entity do not qualify for "A" visa status; they require B-1/B-2 visas. Government officials traveling to the United States to perform non-governmental functions of a commercial nature or traveling as tourists require the appropriate H, L or B visa, or if qualified, travel visa free; they do not qualify for diplomatic visas.

Qualified A visa applicants traveling to the United States for assignments of less than 90 days will be issued visas annotated "TDY" (temporary duty).

Foreign officials who intend traveling to the United States on official business must obtain an "A" visa prior to their entry. They cannot travel on tourists visas, or visa free under the Visa Waiver Program.