United Pet Policy in Cabin: 2026 Fees, Carrier Sizes and Rules Explained

United pet policy in cabin, as of September 2026: United Airlines lets you bring one cat or dog in the cabin (two if you buy an adjacent seat) for $150 each way, according to United Airlines' official pet travel page (2026). The pet must stay in a ventilated carrier under the seat in front of you: soft-sided carriers can be up to 18 x 11 x 11 inches, and hard-sided carriers up to 17.5 x 12 x 9 inches. United has no weight or breed limits. It does not fly pets in cargo for the general public.

The United pet policy in cabin is the set of rules United Airlines applies to cats and dogs that travel as paid pets in the passenger cabin, rather than as service animals or cargo. This guide explains each rule and gives the official source for it. It also covers the federal paperwork that applies when you fly internationally.

By Animal Passport. Last updated September 30, 2026. Airline rules change often, so confirm details on United's official pet page before you book.

United in-cabin pet policy at a glance (2026)

Every row above comes from United Airlines' "Traveling with pets" page, which we checked in September 2026.

How much does United charge for a pet in cabin?

United charges $150 each way for each cat or dog in the cabin, according to United Airlines (2026). A round trip with one pet therefore costs $300 in pet fees. If you bring two pets, you also have to buy a second seat next to your own.

Where sources disagree: some third-party travel guides say United adds another $150 charge for long layovers (more than four hours within the continental U.S. or more than 24 hours internationally). United's current official pet page does not mention a layover surcharge. Ask United directly when you book if your itinerary has a long connection.

United pet carrier size requirements

United has no weight limit for pets. Instead, the carrier sets the limit. It must be ventilated and fit under the seat in front of you, and United states that if it does not fit, "you cannot fly with your pet."

Soft-sided vs. hard-sided carriers

• Soft-sided: up to 11 in high x 18 in long x 11 in wide (27 x 45 x 27 cm), according to United Airlines (2026).
• Hard-sided: up to 9 in high x 17.5 in long x 12 in wide (22 x 44 x 30 cm), according to United Airlines (2026).
• Boeing 737 MAX: the carrier can be no more than 10 inches tall, according to a footnote on United's seating table (2026). An 11-inch soft carrier that fits other aircraft can be refused on this plane.

Most travelers choose a soft-sided carrier because it squeezes slightly to fit under the seat. Check your aircraft type on your booking, because the 737 MAX height limit catches many people out.

How many pets can fly in the cabin on United?

On most United flights, each passenger may bring up to two pets, and the second pet requires a purchased seat next to yours, according to United Airlines (2026). Five narrower aircraft families allow only one pet per person because there is less room under the middle seat: the Airbus A319, A320 and A321neo, the Boeing 737-800/737-8 (MAX 8), and the 737-900/737-9 (MAX 9).

Each flight also has a total pet limit. United's published table (2026) shows:

• Up to 2 pets in premium cabins on aircraft including the A319, A320, 737 family, 757-300ER, CRJ, ERJ 175 and EMB 145.
• Up to 4 pets in Economy on the A319, A320, A321neo, 737, 757-200, 757-300ER, CRJ and EMB 145.
• Up to 3 pets in Economy on the ERJ 175.
• Up to 6 pets in Economy on the Boeing 767, 777 and 787.

Because pet spaces are limited and United accepts pets "if there's space available," book your pet as early as you can.

Where can you sit with a pet on United?

You cannot sit with a pet in an emergency exit row, in a United Premium Plus seat, or in the front row of any cabin, according to United Airlines (2026). Some aircraft have extra restrictions:

• On the Boeing 757-200 in Economy, you must sit in a window seat.
• On the 737-800/737-8 and 737-900/737-9 in Economy, you must sit in an aisle or window seat.

United states that its seating guidance applies to United-operated flights, and that you should contact the airline about United Express flights.

How to book a pet on United: step by step

1. Confirm your destination accepts pets. United does not carry pets to, from, or through several places, listed below.
2. Check your aircraft type to see whether one or two pets are allowed and whether the 10-inch 737 MAX height limit applies.
3. Buy a carrier that meets the size limits and let your pet get used to it before the trip.
4. Add the pet during booking on united.com by selecting "Travel with a pet" as a traveler, or add it later in My Trips. United says pets cannot be added in the United app.
5. Call United for international trips. United requires a phone call to add a pet to an international reservation.
6. Gather your documents: a health certificate, rabies vaccination proof, and any forms required by the Centers for Disease Control and Prevention (CDC) or the destination country.
7. Check in at a kiosk for domestic flights. United says the kiosk prints a special tag for your pet's carrier.
8. On board, keep the carrier closed and under the seat for the entire flight. United describes this as the one rule you must follow on the plane.

Where United does not allow pets

United does not allow pets to fly to, from, or through the following places, according to its 2026 policy page: Australia, Barbados, Brazil, Cuba, Dominica, the Dominican Republic, French Polynesia (Tahiti), Greenland, Guam (with exceptions), Guyana, Hawaii, Hong Kong, Iceland, Ireland, Jamaica, the Marshall Islands, the Federated States of Micronesia, Mongolia, Morocco, New Zealand, the Northern Mariana Islands (Saipan), Palau, the Philippines, Saint Kitts and Nevis, South Africa, Spain (Bilbao only for in-cabin pets), Sweden, Taiwan (specific routes), Thailand, Trinidad and Tobago, the United Arab Emirates (Dubai), the United Kingdom, and Vietnam.

Hawaii is on the list, which surprises many U.S. travelers. United also says that if a trip includes partner airlines, you must check each carrier's own pet policy.

Paperwork for international flights with a pet on United

United requires a health certificate and a vaccination certificate for dogs and cats on all international flights, including flights to Canada and Mexico, according to United Airlines (2026). United also states that rabies vaccination must be completed at least 28 days before travel for both dogs and cats.

Bringing a dog into the United States

The U.S. Centers for Disease Control and Prevention (CDC) is the primary authority for dogs entering or returning to the United States, according to the United States Department of Agriculture Animal and Plant Health Inspection Service (USDA APHIS, 2026). The CDC requires a CDC Dog Import Form for each dog. If the dog is traveling by air, you must show the receipt to the airline before boarding, according to the CDC (2026). If the dog has been in a high-risk country for dog rabies during the previous six months, additional requirements apply, and an unvaccinated dog from a high-risk country will not be allowed to enter, according to the CDC.

Flying to Mexico with a dog

From August 3, 2026, Mexico requires a New World screwworm (NWS) inspection certificate for pet dogs, according to USDA APHIS (2026). A USDA-accredited veterinarian must sign it no more than 5 days before travel. United's page states that the requirement also covers in-cabin pets and service dogs. According to USDA APHIS, pet cats do not need a health certificate or NWS document to enter Mexico, but they are inspected by SENASICA (Mexico's National Service for Agro-Alimentary Health, Safety and Quality) when they arrive.

Domestic trips

For flights within the U.S., United does not require a health certificate but encourages you to get one from your veterinarian, because some destinations may ask for it. United recommends that the certificate include your contact details, your pet's breed, sex, age, color and markings, and its recent vaccines with dates.

Service animals, emotional support animals, and cargo

United states that therapy and emotional support cats and dogs "must fly as pets, not service animals" (2026). That means they pay the $150 fee and stay in a carrier. Only service animals may travel outside a carrier.

United also no longer accepts pets as checked cargo through its former PetSafe program. Cargo travel is limited to certain active-duty military personnel on permanent change of station and State Department foreign service officers, plus their spouses, according to United Airlines (2026). If your dog is too big for an under-seat carrier, United will not fly it in the cabin or in cargo unless it is a qualifying service dog.

How old does a pet have to be to fly on United?

On domestic flights, puppies and kittens must be at least 2 months old, according to United Airlines (2026). On international flights, United requires dogs to be at least 6 months old to comply with CDC requirements, and kittens to be at least 4 months old to meet vaccination rules. Some third-party guides give different international minimums, such as 16 weeks, so rely on United's own page.

Airline pet documents vs. Animal Passport: an important distinction

The paperwork United checks is a veterinary health certificate, rabies vaccination proof, a CDC Dog Import Form receipt, or a USDA-endorsed export certificate. These are official documents issued or endorsed by veterinarians and government agencies such as the CDC and USDA APHIS. Nothing else replaces them.

Animal Passport is a different kind of product. It is a digital animal and livestock identity record built on muzzle biometrics: an animal's nose print is unique, like a fingerprint. Using a phone, the owner captures the nose print, and the record links it to the owner, breed, estimated age (from a dental photo, with a confidence score), a 1–5 body condition score (from a side-profile photo), and vaccination history. In August 2025 it was used in livestock flood rescue in Pakistan, where it helped farmers reclaim animals after their paper ear tags washed away.

Animal Passport is not a government-issued travel document. It is not an EU pet passport, it does not replace a CDC or USDA form, and airlines do not accept it in place of a health certificate. It keeps an animal's identity and history organized. Your travel documents still have to come from your veterinarian and the relevant government agencies. You can find more guides in the Animal Passport blog.

Bottom line

As of September 2026, flying with a pet on United comes down to four things: a cat or dog, a carrier that fits under the seat, a $150 fee each way, and a destination that is not on United's no-pet list. Most problems happen because of the carrier (especially the 10-inch limit on the 737 MAX) or because documents are missing on international trips. Check United's official page and the CDC dog import rules before every trip, because both changed in 2026.