Can you be a citizen of the UK and another country at the same time? For the UK, the answer is yes — but whether you can actually keep both depends on your other country. Here’s how dual citizenship works in 2026: the UK’s rules, the countries that don’t allow it, and the travel and tax points worth knowing.
Does the UK allow dual citizenship?
Yes. The UK permits dual (and multiple) nationality. You do not have to give up your existing citizenship to become British through naturalisation, and British citizens can take another nationality without losing their British status. There’s no separate “dual citizenship” application — it simply happens when you hold two nationalities and both countries allow it.
The catch: your other country
The limiting factor is usually the other country’s law. Many countries require you to renounce your previous nationality when you naturalise, or automatically remove your citizenship if you acquire another. These include (among others) China, India, Japan, Singapore, Indonesia, Nepal, Iran, Saudi Arabia, Qatar, Kuwait and Oman. Always check your home country’s rules before you apply to become British.
Travelling as a dual national
As a rule, use your British passport to enter and leave the UK, and your other passport for that country. Since 25 February 2026, carriers must check your permission to enter the UK before departure, so a dual national travelling on a non-UK passport alone can face boarding problems unless their status is verifiable. Keep your digital status and passports in order, and consider getting a British passport once you’re a citizen.
Tax for dual citizens
Most countries tax you based on where you live (residency), not citizenship, and the UK has tax treaties that generally prevent the same income being taxed twice. The big exception is the United States (and a couple of others), which taxes its citizens on worldwide income wherever they live — so US/UK dual citizens must keep filing US returns. If your finances span two countries, take specialist tax advice.
Other things to consider
- Consular help: the UK generally can’t assist you in a country where you’re also a citizen.
- Military service: some countries impose national-service obligations on their citizens.
- Children: a child can be a dual national from birth if they acquire two nationalities automatically.
Frequently asked questions
Does the UK allow dual citizenship?
Yes. You don’t have to give up another nationality to become British, and British citizens can hold other citizenships.
Do I need to apply for dual citizenship?
No — there’s no separate application. It happens automatically when you hold two nationalities, as long as both countries allow it.
Which countries do not allow dual citizenship?
Many require renunciation or strip citizenship automatically, including China, India, Japan, Singapore, Indonesia, Nepal, Iran, Saudi Arabia, Qatar, Kuwait and Oman. Check your country’s rules first.
Which passport should a dual citizen use to travel?
Use your British passport to enter and leave the UK, and your other passport for that country. Keep your status verifiable for carriers.
Do dual citizens pay tax twice?
Usually not — most countries tax by residence and have treaties to prevent double taxation. The United States is an exception, taxing citizens on worldwide income.
Could I lose my other citizenship by becoming British?
Possibly — some countries automatically remove citizenship when you naturalise elsewhere, so check before you apply.
