What is a short-term assignment?

A short-term assignment is a temporary work arrangement in which a company sends an employee to work in another country for a defined, limited period, commonly under 12 months, though exact thresholds vary by company policy and jurisdiction. The employee retains their employment relationship with the home-country entity and typically returns when the assignment ends. Short-term assignments are also called short-term international assignments or temporary work assignments.

What a short-term assignment involves

A short-term assignment differs from a standard business trip in both scope and duration. Business trips cover meetings, conferences, or exploratory activities over a matter of days. Short-term assignments involve the employee performing substantive work in the host country's operational environment: managing a project, supporting a local team, or transferring specialized skills.

Companies structure short-term assignments around a clear assignment letter or host agreement that defines the assignment duration, compensation structure, responsibilities, and return terms. The employee often stays on the home-country payroll and receives daily allowances to cover local living costs.

Business visitor or work permit: what triggers authorization?

Whether a short-term assignee needs a work permit depends on the nature of their activities and the immigration rules of the host country. Many countries allow business visitors to attend meetings, observe operations, or participate in training without a work permit.

When an employee performs economic work for a host-country business (concluding deals, producing deliverables, or supervising local staff), most host-country immigration authorities require proper work authorization. This distinction matters because misclassification creates risk for both the worker and the company. Workers operating without the right authorization face fines, removal, or future entry bans. Companies face penalties and reputational damage.

Host-country rules vary widely, and teams must confirm authorization requirements for every destination before the assignment starts. Deel Mobility can help teams identify the right authorization for each location.

Tax obligations in the host country

Short-term assignees do not automatically avoid host-country income tax. Under many bilateral tax treaties modeled on the Organisation for Economic Co-operation and Development (OECD) Model Tax Convention, three conditions must apply for an employee to remain taxable only in the home country:

1. the employee is present in the host country for fewer than 183 days in the relevant reference period

2. the salary is paid by or on behalf of a home-country employer

3. the cost is not borne by a permanent establishment the employer has in the host country.

Not every country follows this model, and individual treaties use different day counts or reference periods.

In countries without a tax treaty with the home country, local tax obligations may begin from the first day of employment in the host country. Companies commonly engage tax advisers to run a shadow payroll in the host country to ensure correct withholding without double-paying the employee.

A split-payroll arrangement that divides compensation between home and host countries is another approach used for longer assignments.

Permanent establishment risk

The activities a short-term assignee performs in the host country can create permanent establishment (PE) risk for the sending company. Under OECD guidelines, a PE arises when the company has a fixed place of business in the host country, or when an agent in the host country habitually concludes contracts on the company's behalf.

An employee who negotiates and signs deals, holds inventory, or regularly exercises authority to bind the company may trigger a PE. In that case, the company's attributable profits become subject to corporate tax in the host country.

PE risk increases when assignments extend repeatedly or when the employee's activities expand beyond the original project scope. Clear assignment documentation, a defined scope of work, and legal review before and during the assignment help manage this exposure.

Social security coverage

Most countries require both employees and employers to contribute to social security. Without a bilateral totalization agreement between the home and host country, a short-term assignee can face dual contributions, paying into both systems simultaneously for the same period.

Totalization agreements prevent this by designating one country's system as the applicable one for the duration of the assignment. In the European Union, the home-country social security authority issues an A1 certificate (a certificate of coverage) confirming the worker continues contributing to the home system.

Outside the EU, equivalent certificates apply under bilateral totalization agreements between the relevant countries. Workers should obtain this certificate before the assignment starts.

Per diem vs. relocation package

Short-term assignees typically receive per diem allowances rather than a full relocation package. A per diem is a daily rate covering meals, accommodation, and incidentals for each day the employee works in the host location. Amounts vary by company policy and destination.

A relocation package, by contrast, covers the physical costs of moving: shipping household goods, breaking a home lease, or establishing a new long-term residence. Because short-term assignees generally keep their home accommodation and do not move permanently, a full relocation package rarely applies.

How Deel Mobility supports short-term assignments

Deel Mobility helps companies navigate the immigration and compliance requirements for employees working abroad, including identifying the right work authorizations and managing the documentation process for short-term and international assignments.

Short-term assignments key facts

• Short-term assignments commonly last under 12 months, though the exact threshold varies by company policy and jurisdiction.

• A work permit or other work authorization may be required even for brief assignments if the employee performs economic work in the host country.

• Many bilateral tax treaties based on the OECD Model Tax Convention include a 183-day rule for determining host-country tax liability, but conditions and reference periods differ across individual treaties.

• Permanent establishment risk arises when an assignee habitually concludes contracts or exercises authority to bind the employer in the host country.

• In the EU, the home-country authority issues an A1 certificate confirming home-country social security coverage.

• Equivalent certificates exist under bilateral totalization agreements outside the EU.

• Per diems cover daily living costs during the assignment.

• A relocation package covers one-time physical moving costs and typically applies to long-term assignments or permanent moves.

FAQ

How long is a short-term assignment?

Short-term assignments typically last fewer than 12 months, though the precise boundary varies by company policy and by the tax and immigration rules of the host country.

Does a short-term assignee always need a work permit?

Not always. Business visitor exemptions may apply for purely administrative activities such as meetings or training. Any substantive economic work in the host country generally requires proper work authorization, and the host-country immigration authority defines that boundary.

What is the 183-day rule for short-term assignments?

Under many bilateral tax treaties based on the OECD Model Tax Convention, an employee present in the host country for fewer than 183 days in the relevant period may avoid host-country income tax, provided the salary is borne by the home-country employer and no host-country permanent establishment exists. Rules vary by treaty. A qualified tax adviser can confirm which conditions apply.

What is a certificate of coverage?

A certificate of coverage is a document issued by the home-country social security authority confirming that the employee continues contributing to the home-country system during the assignment. In the EU, this document is called an A1 certificate.

How does a short-term assignment differ from a long-term assignment?

A short-term assignment typically lasts under 12 months. A long-term assignment generally runs for one year or more and usually involves more extensive relocation support, a host-country employment structure, and a broader review of tax residency and social security coverage.

Short-term assignment immigration, tax, and social security rules vary by country and bilateral treaty, and this entry is general context only, not legal or tax advice.