--- title: "How many days can a Spain-based employee work in the UK?" description: "No single day count settles it. HMRC's statutory residence test weighs days and ties, and the UK-Spain tax treaty breaks the tie when both countries claim." canonical: https://www.teamed.global/insights/spain-employee-working-days-in-the-uk datePublished: 2026-09-16T12:00:00.000Z --- Last updated: 16 September 2026 There is no single number that settles this. The UK treats 183 days or more in a tax year as one automatic test of UK residence, under HMRC's [statutory residence test](https://www.gov.uk/government/publications/rdr3-statutory-residence-test-srt). It is only one test among several. Fewer days can still make someone UK resident once their ties to the UK are counted. And if both countries end up claiming the same person, the UK-Spain tax treaty decides which claim wins. So the honest answer is a shape, not a figure. Days matter. Ties matter. The treaty sits behind both. An employee who lives in Spain and flies to the UK most months needs all three looked at together, not one number watched in a spreadsheet. This page sets out that shape and names the official source for each rule. It does not tell you where your own employee will be resident. That turns on facts only you and they hold: where the home is, where the family lives, and how the year really breaks down. A situation we see A UK company with fewer than 100 staff employs a business development manager who lives in Spain. All his customers are in the UK, so he flies over for meetings most months. HR wants to know when his regular travel stops being travel and starts changing where he pays tax. ## Is 183 days the line? Not on its own. Under the statutory residence test, 183 days or more in the UK in a tax year is the first automatic UK test. Meet it and the person is UK resident for that year. But the test does not stop there, and 183 is not a safe ceiling to sit just below. The same test has automatic overseas tests that can settle the question the other way on far fewer days. It also has a ties test for everyone in between. Two people with the same UK day count can land on different answers. The 183 figure is a trigger, not a verdict, and it is only the UK half of the picture. ## What else counts besides days? Ties to the UK count. HMRC's sufficient ties test looks at matters such as family in the UK, available accommodation in the UK, work done in the UK, and time spent here in earlier years. The more ties a person has, the fewer UK days it takes before they are treated as UK resident. That is why a sales role is harder than it looks. The job itself creates a work tie. Regular client meetings create days. A spare room kept at a relative's house can create an accommodation tie. None of these is a problem by itself. Together they move the line down, and they move it quietly. Recent history counts too. Someone who was UK resident in the last three years is judged more tightly than someone who was not. For a person who moved to Spain recently, the first few years are the ones to watch. ## What does the treaty do if both countries claim you? It breaks the tie. Spain and the UK each decide residence under their own law, so one person can qualify in both at the same time. The [UK-Spain double taxation convention](https://www.gov.uk/government/publications/spain-tax-treaties/synthesised-text-of-the-multilateral-instrument-and-the-2013-uk-spain-double-taxation-convention-in-force) published on GOV.UK then decides which country treats that person as resident for the treaty's purposes. Article 4 works through a fixed order. First, the country where the person has a permanent home. If there is a home in both, the country where their personal and economic ties are closer, which the treaty calls the centre of vital interests. If that is unclear, where they habitually live. Then nationality. If none of that settles it, the two tax authorities agree the answer between them. Notice the order. It starts with the home, not the diary. A person can build up UK days and still be treated as resident in Spain, because home and family sit there. The reverse can happen too. Days are evidence towards habitual abode, the third question, not the first. ## Does an A1 certificate fix this? No. An A1 covers social security only. It shows which country's social security scheme a person stays in while they work in another country. It says nothing about income tax and it does not decide tax residence. This is the most common mix-up we hear, and it is worth being blunt about it. In Spain the A1 is issued by the Tesoreria General de la Seguridad Social. The [Spanish government's own guidance](https://administracion.gob.es/pag_Home/Tu-espacio-europeo/derechos-obligaciones/empresas/empleados/desplazados/seguridad-social.html) says it shows the worker stays under Spanish social security law and so does not contribute in the destination country. On the UK side, [GOV.UK](https://www.gov.uk/guidance/social-security-contributions-for-workers-coming-to-the-uk-from-the-eea-or-switzerland) tells employers they can accept a Portable Document A1 as proof that the worker does not pay UK National Insurance for the period on the form. Our [guide to the A1 certificate](/insights/what-is-the-a1-certificate-eu-social-security-guide) covers how it is used. The two questions run on separate tracks. Social security follows the A1. Income tax follows each country's residence rules and, where both claim the person, the treaty. Getting one right does not get the other right. | Question | What decides it | Which document matters | Who issues it | | --- | --- | --- | --- | | Income tax residence | HMRC's statutory residence test, Spain's own residence rules, then the treaty tie-breaker if both countries claim the person | No single form settles it | Not applicable: the tests and the treaty decide the answer | | Social security | Which country's social security law the person stays under while working in the other country | Portable Document A1 | The TGSS in Spain, HMRC for a UK-based worker | ## What should you record, and what if the travel grows? Keep a clean record of every trip. Note the dates in and out, the reason for the travel, and where the work was actually done. Those are the facts a tax authority asks about later, and they are far easier to capture at the time than to piece together two years on. A shared calendar or a simple travel log is enough. Then watch the trend, not just the annual total. A pattern that creeps up matters more than one busy quarter. If UK trips are growing, if the person takes on a home here, or if the family moves, the answer can change from one year to the next. Residence is decided year by year, so last year's position is no promise about this year. Once the pattern shifts for good, the question stops being a day count and becomes a structural one. Where should the role sit, and where should the person be on payroll? Our guide to [payroll for overseas employees](/insights/payroll-for-overseas-employees-complete-2026-guide) covers the mechanics, and the [Spain hiring guide](/country-hiring-guides/spain) sets out what employing there involves. Take those decisions with advice. ## Frequently asked questions These three come up almost every time the topic is raised on a call. The answers are general. Where the honest answer is that it depends on the person, we say so rather than give a number that may not hold for your employee. ### Is the treaty's 183 days the same as HMRC's 183 days? No. They are two different rules that share a number. HMRC's 183 days is about residence and is counted within a UK tax year. The treaty's 183 days sits in its employment income article and is counted over any twelve month period starting or ending in the tax year concerned. ### Does an A1 stop the employee owing UK tax? No. The A1 deals with social security, not income tax. An employee can hold a valid A1 and still have a UK tax question to answer. Treat them as two separate pieces of work. ### Can we just cap his UK days at a set number? A cap is a sensible control, but it proves nothing on its own. A number that is safe for one person is not safe for another, because ties and home life differ. Set the cap with advice, record the trips, and review it when things change. The right answer depends on your employee's situation. [Talk to an Expert](/contact?source=insights-spain-employee-working-days-in-the-uk) at Teamed and we will walk through the Spain and UK side of it with you. You get a real HR and legal expert within 24 hours.