International assignments continue to play an important role in how businesses operate, expand and share expertise across borders. But as more organisations move employees between countries, managing the practical implications of these assignments is becoming increasingly important.
According to ECA’s September 2026 Expatriate Salary Management Survey (ECA International, 2026), 79% of organisations use long-term international assignments to manage operations, 64% to fill skills gaps and 59% to transfer expertise between countries. The same research found that 56% of organisations identify cost containment as a challenge for their global mobility programmes.
The message is clear: international assignments remain valuable, but businesses need to manage them carefully.
Executive summary
- International assignments help businesses manage overseas operations, address skills gaps and transfer expertise.
- ECA’s 2026 research highlights the growing pressure on businesses to control the costs of international assignments.
- Moving an employee abroad can introduce tax, payroll, social security and permanent establishment considerations.
- A clear global mobility strategy helps businesses plan assignments, manage compliance and support employees.
- Businesses should consider these implications before an employee starts working in another country.
What should businesses consider before sending employees on international assignments?
Sending an employee abroad involves more than agreeing on a relocation package and arranging travel. Businesses need to understand the tax, financial and compliance responsibilities that come with having an employee work in another country.
A global mobility strategy provides a framework for managing these responsibilities. It helps establish how assignments are approved, how costs are managed, what support employees receive and which compliance requirements need to be addressed.
Without proper planning, businesses can find themselves dealing with unexpected costs, additional reporting obligations or tax exposure in another jurisdiction.
What you need to know
An international assignment can affect both the employee’s personal tax position and the business’s obligations in the host country.
Some of the key considerations include:
- Tax residency and personal tax: An employee working abroad may trigger tax residency considerations in the host country. Their existing tax position, time spent in each country and ongoing financial connections may all be relevant.
- Payroll and social security: Employers need to establish where salary should be taxed and reported, whether payroll obligations arise in the host country and which social security arrangements apply.
- Permanent establishment risk: Depending on the employee’s role, activities and authority, working from another country could create a taxable presence for the business. This needs to be considered before the assignment begins.
- Assignment costs: Relocation expenses, allowances, cost-of-living adjustments and home-versus-host payroll arrangements should be considered when calculating the true cost of an assignment.
- Employee support: Employees need to understand their tax responsibilities, important deadlines and what is expected of them while working abroad.
These considerations differ between countries and depend on the nature and duration of the assignment. There is no single approach that works for every business or employee.
A real-world example: when an international assignment becomes more complicated than expected
SAIL International recently worked with an engineering group preparing to send a team of twelve employees to West Africa for a two-year project, with some employees expected to move on to the UK afterwards.
The project was already taking shape, but getting the people in place was proving more complicated than simply arranging flights and accommodation. There were tight timelines to work towards, sponsorship licence requirements to address for the UK assignments, and a number of tax, payroll and compliance considerations that the business needed to understand before its employees could move.
Like many businesses undertaking international projects, the company did not necessarily know all the requirements it needed to consider, or how one decision could affect another. With time not on its side, it needed a clear plan and support in coordinating the different aspects of the assignments.
SAIL started by looking at the project from the employer’s perspective. This meant working with the project and finance teams to understand the true cost of moving twelve employees abroad, including accommodation, cost-of-living adjustments, local taxes, social security and potential tax equalisation costs. This exercise highlighted that the actual cost of the assignments was significantly higher than the initial project budget had allowed for.
Alongside the financial planning, SAIL helped identify the relevant country-specific requirements, including employer registrations, payroll obligations, potential permanent establishment exposure and the sponsorship arrangements needed for the UK assignments.
Once the employer’s responsibilities and assignment approach had been established, attention turned to the employees. Each individual needed to understand how the move would affect their personal tax position, what their responsibilities would be in each country and what support they could expect throughout the assignment.
Rather than leaving employees to navigate these unfamiliar requirements themselves, SAIL helped coordinate the process from preparation and departure through to arrival, ongoing tax compliance and eventual return or onward relocation.
The important lesson for other businesses?
The engineering group’s experience highlights an important point: businesses cannot be expected to know every tax, payroll, sponsorship or compliance requirement in every country they operate in. What matters is recognising the complexity early and involving the right specialists before commitments are made.
The earlier these considerations are addressed, the more time businesses have to make informed decisions, allocate the necessary budget and ensure employees are prepared for their move.
So, why does this matter?
International assignments are significant business investments. When the financial and practical arrangements are not properly considered, the consequences can extend beyond unexpected costs.
Delays in getting employees in place can affect project timelines, overlooked employer obligations can create compliance exposure, and uncertainty around personal tax matters can affect employee confidence and wellbeing.
Ultimately, the success of an international assignment depends on more than getting employees to another country. It requires the business to have the right arrangements in place to support the project, meet its obligations and give employees the confidence to do their jobs.
How SAIL International can help
Moving employees across borders requires careful coordination between tax, payroll, financial and employee considerations. Having the right support in place can make a significant difference to how successfully an assignment is managed.
SAIL International works with businesses to plan and manage the tax and practical considerations of international employee assignments.
Through our Global Mobility solutions, we offer:
- Global Assignment Policy Design: Helping businesses establish clear policies and processes for managing international assignments.
- Employer Strategy Sessions: Reviewing business requirements, identifying potential risks and considering the implications of moving employees across borders.
- SAIL Secondment App: Helping businesses and employees keep track of important tax and immigration-related reminders, with a cost-of-living adjustment dashboard.
- Employee Education and Support: Giving employees a better understanding of their responsibilities and providing guidance throughout their international assignment.
Whether your business is preparing for its first international assignment or regularly moving employees between countries, SAIL International can act as your trusted global partner, helping you navigate the tax and compliance considerations along the way.
Planning to send employees abroad?
Speak to SAIL International about our Global Mobility solutions and how we can support your business and its employees across borders.