Travel to the United States is not always linked to tourism, study, business, employment, or permanent immigration. A number of additional visa classifications exist for more specific purposes. These include transit through the US, accessing private medical treatment, carrying out official diplomatic or government duties, engaging in temporary religious work, serving as a crewmember, or entering under humanitarian or special arrangements. This guide outlines these lesser-known visa categories, the eligibility criteria, and how they are used in practice.
Section A: Transit Visas
Foreign nationals passing through the United States on their way to another destination may require a transit visa. The rules depend on nationality, eligibility under the Visa Waiver Program, and whether the traveller intends to leave the airport. Even a brief stop in the US must comply with immigration requirements, and ESTA approval is mandatory for eligible nationals of Visa Waiver Program (VWP) countries.
1. Transit Visa (C)
The C visa applies where the sole purpose of entering the US is to continue a journey to a third country. It cannot be used for sightseeing, tourism, or visits beyond what is necessary to complete onward travel. Extensions or changes of status are not permitted. In practice, consulates frequently advise travellers to apply for a B-2 visa instead if there is any chance of leaving the airport.
2. Visitor Visa (B)
If a traveller intends to leave the airport during a layover, or if the stop involves any short visits, a B-1/B-2 visa may be required. This category allows limited short-term activities in line with standard visitor visa rules. Applications must demonstrate the temporary nature of the stay and plans to continue travel outside the United States.
3. Visa Waiver Program (VWP)
Nationals of designated VWP countries may transit through the US without applying for a visa, provided they obtain ESTA authorisation and meet all programme conditions. Entry is capped at 90 days, including where the purpose is transit only, and no extensions are permitted.
Section Summary: Transit through the US may be covered by a C visa, a B-1/B-2 visa if the traveller intends to leave the airport, or ESTA under the Visa Waiver Program. The appropriate option depends on nationality, eligibility, and whether the traveller intends to remain airside or enter the US temporarily.
Section B: Medical Treatment
Foreign nationals may travel to the United States to undergo private medical treatment. This requires careful preparation, including proof of treatment arrangements, confirmation from a US medical provider, and evidence that the applicant can fund all medical and living expenses. Applicants must also show clear intention to return home once treatment is complete. Admission is never guaranteed, and travellers may be questioned by US Customs and Border Protection (CBP) on arrival.
1. Visitor Visa (B-2)
The B-2 visa is the most common route for medical travel. Applicants must present documentation from a US healthcare provider describing the planned treatment, together with medical records or diagnostic evidence supporting the need for care. They must also prove they can pay for treatment, transport, and accommodation, and that they have strong ties to their home country.
2. Visa Waiver Program (VWP)
Travellers from VWP countries may be admitted for medical care under ESTA if they meet programme requirements. However, their stay cannot exceed 90 days and no extension or change of status is permitted. Supporting documents such as medical confirmation and financial evidence may be requested at the port of entry, and CBP has discretion to deny admission if requirements are not satisfied.
Section Summary: Medical treatment in the US usually requires a B-2 visitor visa supported by medical and financial documentation. Nationals of VWP countries may access treatment under ESTA, but admission is strictly limited to 90 days with no possibility of extension or change of visa status.
Section C: Official Government and Diplomatic Travel
The United States issues specific visas for foreign diplomats, government officials, representatives of international organisations, and military personnel on official duty. These visas reflect the special status of official travel and can extend to eligible dependants. Heads of state and heads of government must always enter the US on an A visa, regardless of the nature of their visit.
1. Diplomatic and Foreign Official Visas (A)
A visas are issued to accredited diplomats and recognised government officials entering the United States on official business. The A-1 visa is for ambassadors, ministers, career diplomats, and consular officers, while A-2 visas apply to other officials or staff on official duty. Immediate family members may also qualify for derivative status. A visas cannot be used for personal travel.
2. International Organization Employees (G) and NATO Visas
G visas are available to employees and representatives of recognised international organisations, such as the United Nations, and extend to qualifying dependants. NATO visas apply to personnel covered by the North Atlantic Treaty agreements and are limited to individuals in specified roles. Both visa types require the applicant to be entering the United States strictly for official duties.
3. Foreign Military Personnel
Foreign military staff assigned to duties in the United States fall under A-2 or NATO visa classifications, depending on their role and assignment. These visas can be renewed if the posting is extended, and immediate family members may also qualify. Military personnel cannot rely on visitor visas for official assignments.
Section Summary: Diplomatic and official travel visas include A visas for diplomats and foreign officials, G visas for employees of international organisations, NATO visas for personnel in covered NATO roles, and A-2/NATO visas for military staff. Dependants are eligible where criteria are met, but these visas are strictly limited to official business.
Section D: Religious, Crewmember, and Humanitarian Visas
Beyond the more common visa classifications, several categories exist for specific roles and humanitarian circumstances. These include visas for religious workers, crew members serving on ships and aircraft, and special entry processes for individuals in need of protection. Each route is governed by strict eligibility and procedural rules.
1. Religious Worker Visa (R)
The R visa allows ministers and religious workers to enter the United States temporarily to work for a qualifying US-based religious organisation. The sponsoring organisation must be a bona fide, non-profit, tax-exempt body recognised under US law. Applicants must provide evidence of their membership, role, and intended duties within the organisation. Employment outside the sponsoring entity is not permitted.
2. Crewmember Visa (C-1/D)
C-1/D visas apply to foreign nationals working as crew on commercial ships or aircraft travelling to the United States. The visa is tied directly to the individual’s crew duties and cannot be used for extended shore leave or work outside the designated role. Crew members may be required to hold both C-1 and D visas, depending on the nature of their journey and stopovers.
3. Humanitarian and Special Situations
Humanitarian entry is not granted through regular visas but through dedicated programmes such as refugee resettlement, asylum, or humanitarian parole. These processes are administered by the US Citizenship and Immigration Services (USCIS) and the Department of State, and they involve separate application and vetting procedures. Family members of recognised refugees and asylees may qualify for follow-to-join benefits under these provisions.
Section Summary: Religious workers can apply for R visas, crew members require C-1/D visas linked to their duties, and individuals in humanitarian circumstances must apply through asylum, refugee, or parole programmes. Each category follows specific rules and processes distinct from standard visitor or employment visas.
FAQs
1. Do all medical visitors need a visa?
Most applicants will require a B-2 visa. Nationals of Visa Waiver Program countries may seek admission for medical treatment under ESTA, but their stay cannot exceed 90 days and no extension or change of status is allowed. Travellers should be prepared to show medical necessity and proof they can cover all related costs.
2. Can a transit visa be used for short sightseeing?
No. A C visa is strictly for passing through the United States en route to another country. Travellers who wish to leave the airport for sightseeing or short visits must apply for a B visa or, if eligible, travel under the Visa Waiver Program with ESTA approval.
3. What is the difference between A and G visas?
A visas are issued to accredited government officials and diplomats undertaking official missions, including heads of state. G visas are reserved for employees and representatives of recognised international organisations such as the United Nations. Both visa categories can extend to eligible dependants.
Conclusion
The United States maintains a broad framework of visa categories beyond the familiar routes for tourism, business, study, and employment. These include transit, medical treatment, diplomatic and government travel, religious work, crew service, and humanitarian programmes. Each category has specific rules, restrictions, and documentary requirements. Choosing the correct visa type and complying with its conditions is vital to secure lawful entry and to avoid problems at the US border.
Useful Links
| US Visas – Official State Department |
| Other Visa Categories – State Department |
| ESTA Application – Official DHS Site |
| NNU Immigration – Other US Visa Categories |
Author
Founder and Managing Director Anne Morris is a fully qualified solicitor and trusted adviser to large corporates through to SMEs, providing strategic immigration and global mobility advice to support employers with UK operations to meet their workforce needs through corporate immigration.
She is recognised by Legal 500 and Chambers as a legal expert and delivers Board-level advice on business migration and compliance risk management as well as overseeing the firm’s development of new client propositions and delivery of cost and time efficient processing of applications.
Anne is an active public speaker, immigration commentator, and immigration policy contributor and regularly hosts training sessions for employers and HR professionals.
