Cohabitation: These laws apply in Switzerland

More and more couples in Switzerland are living together but not getting married, regardless of whether or not they have children. What might once have been referred to as “common-law marriage” is now widespread, but there’s still no explicit legal framework for it. 

Definition: What is cohabitation?

Cohabitation refers to the long-term cohabitation of an unmarried couple and is therefore an alternative to marriage. In a cohabitation, the partners live together based on continuity without getting married. Legally, cohabitation is poorly regulated, which is why the principles of an ordinary partnership are often applied. It offers a great deal of freedom in how people live together, but it also entails legal and financial uncertainties.

What legal issues about children arise for cohabiting couples?

When cohabiting couples have children, important legal questions arise. Unlike married parents, many aspects – such as custody, child support, and adoption – are not automatically regulated. This makes it all the more important to clarify rights and obligations at an early stage and to have these drawn up contractually where necessary.

What are the rules on custody of children?

If the father confirms his paternity at the registry office, you can declare joint custody at the same time. Alternatively, you can do this separately through social services. In the absence of any agreement or registration, the mother legally has sole custody.

In principle, the parents take care of the child jointly to the extent they are able and share the cost of childcare, maintenance, education, and protection. Specific details – including what happens if you separate – can be laid down in a cohabiting agreement. 

Can cohabiting partners adopt children from previous marriages?

Yes. If a couple have been living together for at least three years, they can opt for a “step child adoption” – provided both parents agree to it and it’s in the child’s interest.

Can a couple who are living together adopt children?

Only married couples and individuals can adopt unrelated children. If you want to adopt a child as an individual, you have to be at least 28 years old, and you have to have been responsible for the child’s upbringing for at least a year. You can only adopt if your age and personal circumstances allow you to take care of the child until he or she is 18.

How is home ownership governed for cohabiting couples?

Buying a house or apartment together is a big step for many cohabiting couples. They should be aware that without a marriage certificate, there are no specific legal provisions that apply. Questions about ownership shares, financing, and the division in the event of separation therefore need to be clarified independently and ideally settled contractually.

If a couple buy a house, whose name is entered in the Land Register?

If you buy a house together with your partner, you can decide for yourselves whether one of you is entered in the Land Register as the owner or both of you are entered as co-owners. Co-ownership is the norm where both partners have contributed financially to the purchase.

Who gets the house if the couple separate?

In the event of a separation, you can either maintain or dissolve the co-ownership. If you dissolve it, the house becomes the sole property of one of you, and you have to take financial contributions and any increase in value into account when calculating the buy-out amount.

As with a divorce, both parties can register claims and offer arguments as to why they should get the house. Justified grounds would include the fact that you’ve invested more in the house or that it wouldn’t be fair to take the children out of their familiar environment. This means that it’s a good idea to put down in writing before you buy a house who has to move out if you separate.

What financial and legal special conditions apply to cohabiting couples?

Cohabiting couples bear much greater financial and legal responsibility themselves than married couples. Many of the legal protection mechanisms do not take effect automatically, such as in the case of maintenance, pension provision, or death. That’s why it’s worth knowing the most important rules and risks in detail.

Who is liable for debts?

In general, you’re not liable for the debts of your partner or spouse. Everyone is liable for their own debts. Both partners are liable for debts arising from joint purchases to the extent of their entire assets, even if only one has actually benefited from the purchase. 

If assets are seized as part of a debt collection procedure against one of the partners, it might be impossible to determine who owns what. As a result, assets that actually belong to the partner who isn’t liable for the debt may be seized. This is why it’s advisable to draw up an inventory.

What legal and financial disadvantages does cohabitation have?

For cohabiting couples, both partners bear a greater degree of personal responsibility because there is a lack of central safeguards. For example, there is no automatic entitlement to mutual support during the relationship in the event of separation or in old age. Even in the event of death, the partner is not covered: there is no statutory entitlement to an OASI widow’s or widower’s pension or to a survivors’ pension under accident insurance.

In addition, there is no pension benefits settlement in the event of separation, i.e. assets saved in a pension fund or OASI are not divided, unlike on divorce. In the event of illness or loss of mental capacity, the partner has no automatic right of representation vis-à-vis doctors, banks, or authorities without appropriate powers of attorney.

Cohabiting partners have no right to an inheritance, so it’s important to name your partner as a beneficiary in your will – but make sure you comply with the compulsory shares for children and parents.

You will find more information about Pensions for cohabiting couples in our checklist.

Are there tax advantages for unmarried couples?

Married couples are taxed jointly by law. This has a negative impact for higher-income couples due to progressive tax rates. Cohabiting couples, on the other hand, are taxed individually, so they usually pay less tax than they would if they were married.

However, Swiss voters approved the Federal Act on Individual Taxation in the referendum held on March 8, 2026. This means that in future, everyone will be taxed individually, regardless of their marital status. However, the law does not enter into force immediately, as the Confederation and the cantons must first draft and adapt the exact legal provisions. The law should enter into force by January 1, 2032 at the latest.

You can find more information in our blog article on Marriage or cohabitation.