Our one piece of advice for this whole page: declare everything, every time. It's faster than hoping something slips by, and officers have wide discretion about how the rest of your morning goes. An honest declaration that runs a little over your exemption usually just means paying duty on the difference. An undeclared item found during a search means seizure, fines, and a very long day.
Quick Reference
| Category | Limit | Notes |
|---|---|---|
| General duty-free exemption | $800 USD per person | Covers items for personal/household use, declared to the officer. The usual 48-hour minimum stay is waived coming back from Mexico, so it applies even on a day trip — but you can only claim the full exemption once every 30 days. Families can pool exemptions (two people = $1,600 combined). |
| Alcohol | 1 liter per person 21+, every 31 days | California residents driving back are capped at that federal duty-free liter — B&P Code §23661 means you can't pay duty on extra. Non-California residents driving across may bring up to 60 liters for personal use. Under 21: confiscated, no exceptions. |
| Dogs → into the US | CDC form + microchip + screwworm cert | Dogs must be 6+ months old, ISO-microchipped, healthy on arrival, and carry a CDC Dog Import Form receipt. USDA also wants a screwworm inspection certificate issued within 5 days of crossing. Rabies vaccination isn't federally required from Mexico, but most states require it anyway. |
| Dogs → into Mexico | Screwworm certificate (since Aug 3, 2026) | New rule: a New World screwworm inspection certificate signed by a USDA-accredited vet no more than 5 days before you cross. Pets travel in clean carriers with no more than one day's food. |
| Pets (cats) | Visual inspection at the port of entry | No rabies certificate required for cats, but they can be denied entry if visibly ill. |
| Pet food | 1 factory-sealed 50lb bag per family | Must not contain beef, pork, goat, or lamb — chicken or fish formulas only. |
| Fresh food & agricultural products | Mostly restricted | Most fresh fruits, vegetables, meat, and dairy are prohibited or require inspection — pack processed/packaged snacks instead if you're unsure. |
| Sport-caught fish | Whole or skin-on; US limits apply | Filleting isn't allowed in Mexico, so the catch crosses whole or at least skin-on so officers can identify the species. California won't admit anything it holds at a zero limit (cowcod, canary, yelloweye, bronzespotted rockfish), and where the two limits differ, California's governs. |
| Cash | $10,000 USD (or equivalent) — must declare | Carrying more isn't illegal, but failing to declare it is — and can mean seizure. |
| Prohibited, no exceptions | — | Illegal drugs, most firearms/ammunition without a permit, counterfeit goods, and certain endangered-species products (real tortoiseshell, some coral, etc.). |
Crossing with a Dog
This one has changed twice recently, so read it even if you've been crossing with the same dog for years.
Coming into the US: your dog needs to be at least six months old, microchipped with an ISO-readable chip, healthy on arrival, and traveling with a CDC Dog Import Form receipt — a free online form, but one you have to fill out before you cross. USDA also wants a screwworm inspection certificate issued within five days of the crossing. Rabies vaccination isn't federally required coming from Mexico, which the CDC classifies as low-risk, but nearly every state requires it anyway, so keep the certificate in the glovebox.
Going into Mexico: there's a new requirement as of August 3, 2026, a New World screwworm inspection certificate signed by a USDA-accredited vet and dated no more than five days before you cross. Mexican inspectors will also check that the carrier is clean and that you're not hauling more than a day's worth of food. Build the vet visit into your trip planning — five days is not much runway if your vet books out.
Cats have it easier: a visual inspection at the port of entry, no rabies certificate required, though they can be turned away if they look sick.
Food & Agricultural Products
Most fresh fruit, vegetables, meat, and dairy are restricted or outright prohibited. The rules exist to keep pests and disease out, not to ruin your grocery run. Packaged, commercially sealed snacks are generally fine. When in doubt, declare it and let the officer decide — the worst case is they take your avocados, which beats a fine.
Bringing Back Your Catch
Filleting isn't allowed in Mexico, so sport-caught fish crosses whole or at least with the skin on, because officers need to identify the species. Two things trip anglers up at the line: California won't admit a species it holds at a zero limit even though keeping it was perfectly legal in Mexico — cowcod, canary, yelloweye, and bronzespotted rockfish are the usual suspects — and where the two limits differ, California's wins. Mexico lets you keep five bocaccio, California allows three, so two of them stay behind.
A Note on Alcohol
The federal duty-free allowance is one liter per person 21 or over, once every 31 days. Here's the part that surprises people: if you're a California resident driving back across, that liter is your hard ceiling. California's Business and Professions Code §23661 caps residents crossing by car at exactly the federal duty-free amount, so you can't simply pay duty on a second bottle the way you could elsewhere. Out-of-state visitors driving the same road may bring up to 60 liters for personal use. Under 21, it's confiscated, no discussion.
Absolutely Prohibited
Illegal drugs and most firearms or ammunition without the correct permit are non-negotiable. Don't carry anything you aren't completely sure is legal to transport, and that includes carrying it for someone else. This is also where the “mula ciega” (blind mule) scam matters: never let a stranger put anything in or on your vehicle, and if you've parked somewhere unattended near the border, walk around the car and check the wheel wells, bumpers, and trunk before you get in line.
General guidance only, not legal or customs advice. Limits and rules change — confirm current figures at cbp.gov before you travel, especially for anything you're unsure about.
Last updated August 2026
