How to Import a Horse From Mexico to the US: Santa Teresa Reopens

The short answer, and what's set to change at Santa Teresa

To import a horse from Mexico to the US right now, the horse must pass screwworm inspection and treatment in Mexico and carry a health certificate endorsed by a Mexican government vet, plus an APHIS import permit for US-side quarantine. It then crosses at Santa Teresa, New Mexico, and spends at least 7 days in a USDA-approved quarantine facility on the US side, where USDA tests it for four diseases before release.

USDA's Animal and Plant Health Inspection Service (APHIS) said it would resume land imports of horses and other equines from Mexico through the Santa Teresa, New Mexico, port of entry on Oct. 26, 2026. It's the first equine crossing to reopen since the New World screwworm closures, and for now it's the only one.

The announcement came Oct. 20 as part of a phased reopening of southern border ports. Columbus, New Mexico, was scheduled to reopen to cattle on Oct. 26 as well, with Nogales, Arizona, penciled in for cattle on Nov. 30 if conditions allow.

A few things to keep straight:

• This is a scheduled reopening. As of this writing, we haven't seen confirmation that the first horses have crossed.
• Quarantine is on the US side only. The quarantine facilities on the Mexican side of the port stay closed.
• Other ports will wait. USDA says it will judge how the new safeguards work at Santa Teresa before opening other crossings or Mexican-side quarantine barns to horses.

Why so cautious? Screwworm is a fly whose larvae feed on living tissue in open wounds. USDA has confirmed dozens of US cases since June, almost all in Texas, and in September it confirmed a case in a horse in Grant County, New Mexico, about 150 miles from the Santa Teresa port. For background on the parasite itself, read our guide to New World screwworm in horses.

How to import a horse from Mexico to the US, step by step

Here's a practical order to work through it. Treat it as general information, not legal advice.

1. Line up the US quarantine and the permit first

Horses that complete quarantine at an APHIS-approved US facility need an APHIS import permit issued before export. Don't buy a trailer slot until the permit and a quarantine reservation are in hand.

2. Check residency and recent vet work

• The horse must have been in Mexico for 60 days before import. If not, you need export certificates from every country it lived in during that time.
• No vaccines in the 14 days before export.
• No castration in the 14 days before export. Plan gelding well ahead or wait until the horse is home.

3. Know which blood tests the horse will face

These tests aren't done in Mexico before export. USDA staff draw blood once the horse is in US quarantine and send the samples to the National Veterinary Services Laboratories in Ames, Iowa. The horse must test negative for:

• Equine infectious anemia (EIA), the Coggins test. See What is a Coggins test?
• Equine piroplasmosis, by complement fixation test (CFT) and cELISA, the official entry tests
• Dourine
• Glanders

A horse that isn't negative on these tests is refused entry. Horses that lived in a country affected by contagious equine metritis (CEM) in the past 12 months use a different certificate and need CEM testing too.

4. Get the health certificate

A veterinarian examines the horse and issues the certificate within 30 days of the physical exam. It must be endorsed by a Mexican government salaried veterinarian. It also confirms a negative check for ticks and other external parasites.

5. Screwworm treatment before loading

• 3 to 5 days before export: treatment with ivermectin or another APHIS-approved product, recorded on the screwworm addendum to the health certificate.
• Within 24 hours of shipping: a negative screwworm exam.
• At loading: any visible wound is treated with an APHIS-approved screwworm product.

6. Book the crossing

USDA's general Import Horses From Mexico page says to contact the port at least 3 business days ahead, but the guidance for this crossing asks for more. You or your broker must send USDA Veterinary Services at the port a written service request at least 72 business hours before the horses arrive. Port business hours are 8 a.m. to 4:30 p.m., Monday through Friday, so that's more than 8 business days, not 3. A copy of the government-endorsed health certificate and its supporting papers is due at the port at least 48 business hours before inspection. Each port can add its own requirements, so ask whether it requires an authorized customs broker; some do.

7. Quarantine on the US side

The horse goes to a USDA-approved facility on the US side for a minimum of 7 days. That's when USDA draws blood for the four tests and checks the horse daily. If a test or exam raises a question, plan for the stay to run longer.

Timeline at a glance

On costs, APHIS says its fees at land border ports match the services provided. The daily quarantine rate covers exams, routine vet care, feed and bedding, sample collection and shipping, and paperwork checks. Ask the facility and your broker for a written quote; budget for transport on both sides and a few extra days in case results are delayed.

Checklist for owners, charro families and buyers

Print this, or screenshot it before you talk to a seller in Mexico.

• APHIS import permit approved
• Quarantine space reserved at a USDA-approved US-side facility
• Customs broker confirmed, if the port requires one
• Horse in Mexico at least 60 days, or extra export certificates
• No vaccines and no castration in the last 14 days
• Health certificate within 30 days of the exam, endorsed by a Mexican government vet
• Ivermectin treatment 3 to 5 days before export, written on the addendum
• Negative screwworm exam within 24 hours of shipping
• Written service request sent to the port at least 72 business hours before arrival
• Copy of the health certificate and papers at the port at least 48 business hours before inspection
• Budget for a stay that could run longer than 7 days while USDA's EIA, piroplasmosis, dourine and glanders results come back
• Ride home lined up for release day

If you're buying an Azteca or Quarter Horse

If you're buying an Azteca horse, a Quarter Horse or a charro horse from a Mexican breeder, do this before you pay:

• Make the sale conditional on passing the import tests. A horse that tests positive on any of them can't be imported.
• Get the registration papers sorted (AMCCRA for Aztecas, AQHA for Quarter Horses) so transfers aren't held up later.
• Order a pre-purchase exam from a vet you trust, separate from the export exam. Our pre-purchase exam guide explains what to ask for.

If you're a charro or rodeo family

If you've been waiting to bring a horse up for the charreada or rodeo season, don't plan around a specific competition date yet. With one port and limited quarantine space, waits are possible, and the 7 days in quarantine come on top of travel.

Once the horse is home

Release from federal quarantine doesn't mean the horse should go straight into the herd. Keep it apart for a couple of weeks, take its temperature daily and check for any wound, especially around the navel, sheath, ears and any cuts. Our guide to quarantining a new horse walks through the setup.

Also check your state's own entry rules. Some states want their own paperwork or a recent Coggins on arrival, and many shows require a current Coggins. Our health basics pages cover routine care for the first weeks.

If you see a wound with larvae, or one that smells bad or keeps getting bigger, call your vet and your state veterinarian right away. Screwworm is a reportable disease.

What to watch next

• How Santa Teresa goes. USDA says it will evaluate the safeguards there before expanding. That evaluation decides when other ports reopen to horses.
• Mexican-side quarantine. USDA says approved facilities in Mexico may be considered later. That could ease the bottleneck.
• Screwworm cases. A new case near the border could pause crossings again with little notice.
• Cattle ports. Columbus (Oct. 26) and Nogales (scheduled Nov. 30) show how fast USDA is moving overall.

Before you book anything, check the APHIS Import Horses From Mexico page and call the port. The rules on this page reflect what APHIS posted as of Oct. 20, 2026, and they can change quickly if screwworm cases shift.

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