The apostille and the perito traductor, in the right order.

The chain, in order

1. Get a recent certified copy of your birth certificate from the civil registry in the country that issued it. Some authorities will only apostille a recent copy.
2. Have it apostilled by the competent authority in that same country — never in Mexico. Mexico cannot apostille a document another country issued.
3. Have the whole thing translated into Spanish by a perito traductor authorized by the judiciary in Mexico, including the apostille itself.
4. File it with SRE, with the original certified copy, its apostille and the translation together.

The order is the part people get wrong. If you translate first and apostille second, the translation does not cover the apostille and you pay for a second one.

What an apostille actually is

An apostille is a certificate that authenticates the signature and seal on a public document, under the Hague Convention of 1961. It does not say your birth certificate is true. It says the official who signed it really holds that office.

It is issued by the country that issued the document. If your country is not part of the Hague Convention, the equivalent is consular legalization, done through the Mexican consulate there. The Reglamento asks for the document "legalizada o apostillada" precisely because both routes exist.

Plan for weeks rather than days, especially if you are arranging it from Mexico through a relative or a service in your home country.

What a perito traductor is

A perito traductor is a translator authorized by the judiciary in Mexico — a state superior court or the federal judiciary publishes the list. It is a legal status, not a quality rating: a bilingual friend, a professional agency translator or a sworn translator from another country are all not a perito traductor for this purpose.

Two words worth separating, because Spanish-language guides written in Spain confuse this: in Spain the role is a traductor jurado. In Mexico the term SRE uses is perito traductor. Ask for the right one.

• Use a perito on the list for the state where you will file.
• Ask for the apostille to be included in the translation, not just the certificate.
• Check the spelling of every name and place before you accept the work. A misspelling here is a mismatch with your other documents.
• Keep the translator’s stamp and credentials with the document.

What else may need it

• A foreign marriage certificate, for the marriage route.
• A foreign criminal-record certificate, if SRE asks for one covering time abroad.
• A document proving a second-degree descendant has no other nationality, which the Reglamento specifically requires legalized or apostilled and translated into Spanish.

Documents issued in Mexico — a Mexican birth certificate, a Mexican marriage certificate, a Mexican criminal-record certificate — need neither. They are already in Spanish and already domestic.

The mistakes that cost time

• Translating before apostilling, so the translation does not cover the apostille.
• Apostilling a photocopy rather than a certified copy from the civil registry.
• Using a translator who is not a perito, however good the translation is.
• Starting the chain a month before the appointment. Start it the day you book.
• Letting the certified copy go stale while the rest of the file comes together.

The full document list