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LetterAgent cannot mail letters to Mexico: it serves US and Canadian addresses only. To mail a letter to Mexico yourself, address it in the Mexican format with the five-digit postal code before the city, use international postage from your own country's post office, and expect delivery to take longer than domestic mail.
Mexican addresses read differently from US ones, and the order matters for sorting. Write the recipient's name first, then the street name and number, then the neighborhood (colonia), then the postal code, city, and state, with MEXICO as the final line in capital letters. A typical layout looks like this:
The colonia line is the detail senders most often skip, and it is often the line that matters most. Mexican cities can have several streets with the same name in different colonias, so the neighborhood narrows the delivery area in a way the street name alone cannot. If your recipient gives you a colonia, include it exactly as given. The postal code, called the codigo postal, has five digits and sits before the city name, not after it as in US addresses.
Use international postage from the post office of the country you are mailing from, and buy it for Mexico specifically. A domestic stamp does not cover an international letter, and an international letter with short postage may be returned to you or delivered with postage due at the other end, which often means it is never collected. If you are mailing from the US, ask at the counter for the current international letter rate to Mexico, or use the post office's online postage tool to print the right amount.
Put your own return address on the envelope, in the upper left corner, with your country name as the last line. A return address matters more on international mail than on domestic mail: if Mexican customs or the postal service cannot deliver the letter, a clear return address is what sends it back to you instead of into a dead-letter pile.
| Step | What to do | Why it matters |
|---|---|---|
| Address format | Name, street and number, colonia, postal code, city, state, MEXICO | Sorting machines and carriers use the colonia and postal code to route the letter |
| Postage | International rate to Mexico, bought from your own post office | Short postage can mean return or delivery with postage due |
| Return address | Upper left corner, with your country on the last line | Lets undeliverable mail come back to you |
| Contents | Keep it to documents; goods go through a different channel | Goods in a letter envelope can be stopped at customs |
Longer than domestic mail, and less predictably. The letter crosses two postal systems: yours hands it off at the border, and Correos de Mexico, the Mexican postal service, carries it from there. Urban addresses in Mexico City, Guadalajara, and Monterrey generally see faster delivery than rural addresses, where delivery may run through a local post office for pickup rather than to the door. Tracking on a basic international letter is limited: you may see the departure scan from your own country and little after that until delivery.
If the letter is urgent, registered international mail is the usual upgrade. It adds tracking and a signature on delivery, and it gives you a claim path if the letter goes missing. For truly time-critical documents, a courier service is the safer choice, since couriers run their own networks end to end and report each handoff.
Letters are for documents: contracts, invitations, personal letters, and certificates. Anything that looks like merchandise, a sample, a gift item, or a product, belongs in a parcel with a customs declaration, even if it physically fits in an envelope. Customs officers open envelopes that seem to hold goods, and an undeclared item can be seized or returned. Cash should never go in an international letter: it is a theft risk and it is restricted in many postal systems.
Documents themselves are normally duty-free, but a thick bundle of documents can still draw a customs look. If you are sending a large set of documents, a short note inside describing them helps, and a courier with a proper waybill avoids the ambiguity entirely. Keep a copy of anything important you send abroad: replacing an original certificate that vanished in international mail is slow and sometimes impossible.
The flow reverses cleanly: the sender in Mexico buys postage from Correos de Mexico, addresses the envelope in the destination country's format, and writes MEXICO as part of their return address. Delivery within the US or Canada then follows the domestic system. One practical wrinkle is that Correos de Mexico delivery standards vary by region, so a letter mailed from a small town may take longer to leave Mexico than one mailed from a city post office.
If you are waiting on a letter from Mexico, ask the sender for the tracking number if they used registered mail, and check with your own post office if it stalls. International inquiries usually have to be opened by the sender's postal service, not the recipient's, so the sender is the one who can start a trace.
Ready to mail it? Send your letter with LetterAgent: describe it to your AI assistant, approve the exact quoted price, and it is printed and mailed.
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