In Argentina it is possible to obtain permanent residency through the registration of a civil union, provided certain requirements established by Dirección Nacional de Migraciones) are met.
A civil union is a legal figure recognized by the Argentine Civil and Commercial Code, which allows unmarried couples to formally register their cohabitation.
To be valid, the couple must:
Be of legal age.
Not be related in a direct blood line or be siblings.
Not be married or already in another registered civil union.
Have lived together for at least two years, unless they have children together.
The registration must be carried out at the Civil Registry corresponding to the couple's place of residence.
Requirements to apply for permanent residency
If you are a foreigner and your partner is an Argentine citizen (either native-born or naturalized) or a permanent resident in Argentina, you can apply for permanent residency by submitting:
A certified copy of the registered civil union.
The DNI (national ID) of the Argentine citizen or permanent resident (the sponsor).
A police clearance certificate from Argentina and from your country of origin or any country where you have lived in the past three years (for those over 16 years old).
Proof of legal entry into the country.
Proof of residence in Argentina.
You must start the process through the RADEX platform.
Importance of the civil union registration
Resolution 4880/2015 from Migraciones ( google it ) recognizes registered civil unions with similar legal effects to marriage for immigration purposes.
This means that once registered, a civil union allows the foreign partner to access similar immigration benefits as a spouse.