Last Mile Across Mexico: Coverage, Postal Codes and Attempt Policy

Ask a provider whether they deliver across Mexico and the answer is almost always yes. That answer is not useful. Coverage on this lane is a list of postal codes with a service level attached to each one, and the gap between the codes a network serves daily and the codes it serves eventually is where delivery promises break.

This article covers what a Mexican postal code actually encodes, which parts of a Mexican address are mandatory and which are not, and how to read a coverage claim so that it means something at checkout.

Coverage is a list of postal codes, not a map

A map implies a boundary and delivery networks do not work on boundaries. They work on route density. 2 addresses 3 streets apart can sit in different service tiers because 1 is on a daily route and the other is on a route that runs when there is volume for it.

So the question worth asking a provider is not which states they cover. It is whether they will supply the postal code list, and what the service level is against each code. A provider who cannot supply the list is describing an intention rather than a network.

What a Mexican postal code actually encodes

"Clave numérica compuesta por cinco dígitos que identifica y ubica un área geográfica del país y la oficina postal que la sirve, para facilitar al correo, el encaminamiento, la distribución y el reparto de la materia postal."

Servicio Postal Mexicano, Manual de Asignación de Códigos Postales y Estandarización de Domicilios Postales

The structure is not arbitrary and the same manual sets it out. The first 2 digits identify a federal entity. The third identifies a municipality or a group of them. The last 2 narrow it to a settlement.

Two practical consequences follow. A postal code identifies a settlement rather than a street, so it never completes an address on its own. And because the code is hierarchical, a validation rule that checks the code against the settlement name catches a large share of mistyped addresses before dispatch rather than after.

The economics of the outcome after the last attempt are worked through in Dropshipping Returns From Mexico: Local Address, Restocking and Re Entry.

The address has 12 components and 5 of them are mandatory

"El domicilio postal es el conjunto de información, que para un envío postal, permite la determinación precisa de un punto de entrega verdadero o potencial, usualmente combinado con la especificación de un destinatario y/o un remitente."

Unión Postal Universal, Norma Internacional S42, citada en el manual del Servicio Postal Mexicano

For a delivery made to an address by a carrier, the manual lists 12 components. Only some are obligatory, and knowing which is the difference between a checkout form that works and 1 that generates support tickets.

The row that catches US sellers is Vialidad. It carries the exterior number, and an address without 1 is not a weak address, it is an incomplete one.

The country line is required only on international origin, which is you

The manual marks País as required only for pieces of international origin. A domestic Mexican seller can leave it out. A US seller cannot, and a checkout that hard codes the destination country into a hidden field rather than printing it on the label produces parcels that are correct in the database and ambiguous on the box.

It is a small thing and it costs nothing to fix. It is also the kind of thing that gets discovered on the 400th order rather than the 4th.

The 3 coverage tiers, and what changes between them

• Daily route. The major metropolitan areas. Delivery attempts happen on a fixed schedule and a failed attempt is retried the next working day at no meaningful cost.
• Scheduled route. Secondary cities and the edges of metropolitan areas. Attempts happen on the days the route runs, so a failed attempt can cost several days rather than 1.
• On demand or agency. Remote areas, where delivery is arranged rather than routed. Here the realistic service is often collection from a local office rather than delivery to the door, and pretending otherwise at checkout creates the complaint.

The tiers matter because the attempt policy that is generous in tier 1 is expensive in tier 3. The same 3 attempts that cost nothing on a daily route can hold a parcel for 2 weeks where the route runs twice a month.

Price the tiers rather than averaging them. A seller charging 1 flat delivery fee across all 3 is overcharging the 80 percent of orders that land on a daily route in order to subsidize the few that do not, and is still losing money on the tier 3 orders. Two rates, or 1 rate plus a named surcharge list by postal code, is more honest and usually cheaper for everybody.

Attempt policy belongs in the contract, not in the assumption

There is no national standard for how many times a carrier tries. It is a commercial term, and a seller who has not agreed it has agreed to whatever the network does by default.

Three things need naming: how many attempts, where the parcel waits between them, and what happens after the last one. The third is the expensive one. Held for collection, delivered to an alternative address, returned to a Mexican address, or re-exported are 4 outcomes with 4 very different costs, and the difference between the cheapest and the most expensive is larger than the delivery fee that started it.

The arithmetic on the last outcome is worth stating, because it is the one sellers price at zero. A parcel that has cleared into Mexico has been imported. Sending it back to the US is an export from Mexico followed by a US entry, and the duty and the 16 percent IVA already settled on the way in do not return by default. A fresh entry carries its own charges as well: the customs processing fee is 8 per thousand of customs value with a floor of 258.91 pesos, and brokerage runs 3,500 to 15,000 MXN. On a parcel worth 60 dollars, that is a recovery that costs more than the goods 3 times over.

Which is why the outcome after the last attempt should almost never be re-export. Held for collection for 5 to 10 days, then returned to a Mexican address, keeps the unit inside the country where it is still sellable.

Where deliveries fail, and it is rarely the carrier

The recurring causes are addressing rather than routing. A missing exterior number. A settlement name that does not match the postal code. A street name entered where the settlement belongs, which happens constantly because US address forms have no field for a colonia. And nobody present, which in Mexico is less common than sellers expect because a neighbor or a doorman routinely receives.

None of these are fixed by choosing a better carrier. They are fixed 1 step earlier, at the point the address is collected.

Checkout is where most last mile failures are created

A US storefront collects a 2 line address. A Mexican address needs the exterior number, the settlement type and name, the 5 digit code, and both the municipality and the federal entity. Squeezing that into 2 lines guarantees that something lands in the wrong field.

Three changes remove most of it. Give the exterior number its own field. Give the colonia its own field rather than letting it share a line with the street. And validate the postal code against the settlement at checkout, where a buyer can still correct it, rather than at dispatch, where they cannot.

The 4th change is to stop treating the interior number as optional in apartment buildings. It is the component that separates 1 delivery point from 40 in the same tower, and a carrier holding a parcel for a building with 12 floors and no unit number will either guess or return it.

Rural addresses, where there is no street to name

Outside urban areas the manual's own examples stop using street names at all. A valid rural address can read as a road, a side of that road, and a kilometer marker, or as a settlement plus a reference such as 900 meters northeast of a named landmark.

That is not a broken address. It is the correct form for that location, and a validation rule written against urban addresses will reject it. A seller who blocks these at checkout has quietly stopped selling to a part of the country, and will read the result as low demand rather than as a form that refuses the order.

How that final step connects back to the customs process upstream is covered in Door to Door US to Mexico: What Tracking and Proof of Delivery Actually Prove.

How BringGo Ship Handles This

BringGo Ship delivers to addresses across Mexico from stock held at our Laredo facility and inside the country, and our team works from the postal code list rather than from a coverage claim, so a seller can see the service level against the codes their orders actually come from. Attempt policy, the wait location and the outcome after the last attempt are agreed before the first shipment rather than discovered on it. Address quality is checked at receipt, which is where a missing exterior number is still cheap to fix.

Frequently asked questions

Is a postal code enough to deliver? No. It identifies a settlement and the postal office serving it. The street, the exterior number and the settlement name do the rest of the work.

Why do orders from the same city get different delivery times? Route density rather than distance. 2 addresses in the same city can sit on a daily route and a scheduled route respectively.

Should I block remote postal codes at checkout? Price them rather than block them. A code served by collection at a local office is still a sale, provided the buyer is told that is what they are getting.

What single change reduces failed deliveries the most? A separate field for the exterior number, validated as non empty. It is the most frequently missing mandatory component and the one a carrier cannot work around.