Dual Citizenship: Everything You Need To Know As An Expat

Dual citizenship is, as the name suggests, when you are considered a full citizen of two (or more) countries.

It’s important to know that while there are many benefits to dual citizenship, there are also a number of challenges you might face. In this guide, we’ll run through some of the most common questions people ask about dual citizenship – including how it might affect your entitlement to healthcare and health insurance.

Everything you need to know about duel citizenship

Obtaining dual citizenship can be tricky. You can only become a dual citizen of two countries that both agree to allow you to do this.

However, it’s more common than you might think in an increasingly globalised world – for instance, 1,236,000 people in the UK hold dual citizenship (around 2% of the country, or 1 in 50 people).

If you’re an expat who has been living and working abroad for a while, you may be thinking about applying for dual citizenship. Likewise, you may be thinking about dual citizenship if you’re marrying a foreign citizen, if you’ve had a child abroad, or if you’re purchasing property.

It’s always a good idea to have international health insurance

But did you know some countries require it for entry?

What is dual citizenship and how does it work?

Dual citizenship, also known as multiple citizenship, dual nationality or second citizenship, is when a person holds the legal status of ‘citizen’ in two or more countries. This means the person is:

• Considered a full citizen under the laws of those countries
• Entitled to all the rights of a citizen in all countries, including the right to hold a passport, the right to work, to own property, to vote and the right to consular support
• Also potentially subject to the obligations of citizenship in those countries, including the obligation to pay taxes or to take part in national service

Dual citizenship has a long and complicated history. The Bancroft Treaties signed by the United States and European countries between 1868 to 1937 made it law that a citizen of one country who settles in another must give up their previous citizenship, so by the mid-20th century it was extremely rare to find countries that allowed dual citizenship.

However, as global travel became easier and as legal challenges against citizenship laws started to mount up, many countries warmed to the concept. In 1948, the British Nationality Act permitted dual citizenship in the UK, followed by the Canadian Citizenship Act of 1976.

The Bancroft Treaties collapsed throughout the 1990s, which made it possible for European countries and the US to follow suit. Even today, countries are still updating their citizenship laws to allow dual citizenship – for instance, Germany only started allowing dual citizenship in June 2024.

That said, not every country allows dual citizenship, and in order to become a dual citizen both countries must allow dual citizenship under their own laws. Around 49% of countries in the world allow dual citizenship. However, there may be certain restrictions and barriers, even within those countries.

Rules and eligibility criteria for dual citizenship can vary significantly between countries. It’s important to do your research and always check the specific laws and requirements of both your current nationality and the country where you’re seeking citizenship.

Are you thinking about moving abroad?

Check out our guide to living and working abroad

Which countries allow dual citizenship?

Many countries allow dual citizenship, although some countries impose restrictions on who can obtain citizenship and which countries they can combine citizenship with.

The following list contains the 71 countries that recognise and allow full, unrestricted dual citizenship with all other countries in most cases.

*Except with South Sudan

Where are the best countries to live in the world?

We rank the best countries to live and work abroad

Which countries don’t allow dual citizenship?

Any country not mentioned above will either not allow dual citizenship or considers it a legal grey area (meaning dual citizenship may technically be possible, but could lead to problems).

The countries that explicitly do not allow dual citizenship are:

Expat tax matters can get tricky

Here’s everything you need to know about taxes for expats

How can I obtain dual citizenship?

In order to obtain dual citizenship, you will first need to meet the citizenship criteria of another country. There are a number of channels by which you can become the citizen of a second country, which include:

Dual citizenship by naturalisation

Naturalisation occurs when you are considered eligible to apply, or automatically enrol for citizenship in another country. It means you have ‘naturalised’ into that country’s society and economy and can legally be considered a part of that country.

Naturalisation typically occurs once you have lived in another country for a certain number of years. Most countries will state a minimum number of years that you must live in that country continuously in order to be eligible for citizenship.

Naturalisation is not always an automatic process. Even after residing in a foreign country for some time, you may still need to complete certain tasks in order to be considered for citizenship.

For instance, in the UK, you must:

• Have lived in the UK for five years or more, or have EU settled status
• Pass the Life in the UK test, which tests your knowledge of the history and political structure of the UK
• Pass an English language test
• Be able to prove you are “of good character”
• Submit your biometric information
• Pay the application fee of £1,630

You can then apply for citizenship at the Home Office. If successful, you will undergo a citizenship ceremony which includes swearing an oath of allegiance to the United Kingdom.

Assuming your country of origin and new home country both allow dual citizenship, you will either:

1. Not have to give up your original citizenship in order to become a citizen of your new home country, or
2. Be able to apply for dual citizenship status through either one, or both government channels of those countries

Living abroad comes with its own set of challenges

Discover some disadvantages and how to overcome them

Dual citizenship by marriage

Some countries will allow you to become a citizen through marriage. In certain countries, marriage grants you automatic citizenship. However, each country is free to determine the eligibility of individuals who marry, and may impose certain restrictions. 

For instance, you may need to reside in your spouse’s country for a certain period of time, or you may need to undergo a citizenship test. Some countries may also strip you of your citizenship if the marriage ends. The rules for each country may be different for men and women, and certain countries may not recognise homosexual marriages as eligible for granting citizenship.

Assuming both your country of origin and new home country allow dual citizenship, and if you fulfil all of the necessary criteria for citizenship, you should be able to enjoy dual citizenship.

Moving abroad to further your partner’s career?

Here’s how to make the best of your new life as an expat spouse

Dual citizenship by ancestry

Countries will determine the right of newborn children to inherit citizenship based on two principles. The first is jus sanguinis, the right of blood; the second is jus soli, the right of soil. Some countries may observe just one principle, while others may observe both:

• Jus sanguinis means that you can be considered a citizen of a country so long as you are ethnically part of, or descended from that country. For instance, if one or both of your parents is a native citizen, or if you are able to prove descent through historic birth records. This means you can apply for citizenship, even if you were born abroad. Countries that observe jus sanguinis include China, India, Japan, South Korea, the US, Canada and most European countries.
• Jus soli means that you will automatically be considered a citizen of the country you were born in. Jus soli may not apply automatically if you were born to non-citizen parents, and you may need to apply later in life after having grown up in that country. Countries that observe jus soli without restriction include Canada, Mexico, Argentina, Brazil and Pakistan.

Some countries may allow retrospective applications for citizenship based on these principles. For instance, if you were born in the UK to Irish parents and have British citizenship, you can apply for dual Irish citizenship. Likewise, if you were born in the UK to Irish parents and given Irish citizenship, you will later be eligible to apply for dual British citizenship.

In any case, you will need to be aware of the exact laws governing birthright citizenship in the country or countries you wish to apply for citizenship for.

The concept of family forms the bedrock of society

We explore how attitudes toward family differ around the world

Dual citizenship by property purchase

Some countries offer citizenship to those who purchase property in that country, also known as ‘citizenship by investment’. Countries that are open to this policy include Antigua and Barbuda, Dominica, Grenada, Malta, Saint Kitts and Nevis, Saint Lucia, Türkiye and the UAE (in some cases).

The exact rules will vary by country, and the route to obtaining citizenship through property purchase is not always straightforward. Most countries will also specify a minimum property value that you must complete a purchase on.

For instance, to gain Maltese citizenship through property purchase you must:

• Be over 18
• Hold a valid residence card
• Be in good health
• Purchase a residential property worth at least €600,000 if you have lived in Malta for 36 months, or €750,000 if you have lived in Malta for 12 months
• Hold the property for at least five years
• Donate €10,000 to an organisation approved by the Community Malta Agency

Some countries offer property purchase as a gateway to citizenship. Non-EU citizens can purchase property in Greece, for example, which offers permanent residency and, after seven years, opens the doors for them to become full citizens.

Purchasing your own home is one of the greatest joys in life

Where are the best and easiest countries to buy property abroad?

If I have dual citizenship, which passport should I use?

Obtaining dual citizenship may allow you to visit countries that your previous passport did not allow you to enter, or to visit countries visa-free. So long as at least one of your passports allows you to enter or exit a territory, this is the passport you should use when travelling to that country. You must ensure you use only one passport for the entire duration of each trip, especially if you will be crossing multiple borders.

When entering or exiting a country that you hold a passport in, you must usually use that country’s passport at immigration control. This means you may need to travel with two or more passports. 

For instance, if you have dual US and British citizenship, and you are travelling from the US to the UK, you will need to show your US passport to leave the US, then show your UK passport to enter the UK – but you may need to show proof of your US exit stamp when arriving in the UK.

If you are unsure which passport to use, it’s best to contact the embassy or consulate of the country or countries you will be visiting.

Don’t let culture shock get you down

Read our guide to help you settle into your new home

How does dual citizenship affect my international health insurance?

While we cannot speak for other health insurance providers, as a William Russell member you will find that your dual citizenship offers you an additional level of flexibility.

Ordinarily, we are only able to provide international health insurance if you are living in a foreign country. We’ve emphasised those words because if you are living in a country where you hold citizenship, we would usually not be able to offer you international health insurance.

However, as a dual citizen, we are able to class you as an expat even if you are living in one of the countries you hold citizenship. This is because we will use your other nationality as your main one for insurance purposes.

So, for instance, if you have dual British and French citizenship and are living in France, we can classify you as a British citizen living abroad, rather than as a French citizen living at home.

This may make it easier for you, as you will not need to switch to local health insurance or rely on state healthcare, and can continue to access the benefits of your William Russell insurance policy.

This rule also counts if you already have an international health insurance policy and are applying for dual citizenship in the country you are living. After your dual nationality is granted, we will continue to classify you as a citizen of your original country for insurance purposes.

If you are a dual national and planning to move to a country where you hold citizenship, you should alert us before you move, as we may need to change the main nationality on your policy. Please note this may affect the cost of your premiums and, if you do not inform us, may also affect your ability to make a claim.

If in doubt, speak to our award-winning customer service team today. They’ll be happy to take you through your policy options.

International health insurance, tailor-made for expats

At William Russell, we have over 30 years’ experience providing international health insurance to expats like you. Our flexible policies give you access to the highest-quality healthcare all over the world, with optional extras to suit your needs and medical evacuation insurance included as standard.

Find out more about our international health insurance policies and get a quote online in under two minutes.