Short answer: Allegiant lets small dogs and cats fly in the cabin on flights within the 48 contiguous states for $50 per carrier on each flight, in a soft-sided carrier of up to 18 x 12 x 11 inches or a hard-sided one of up to 17 x 11 x 10.5 inches.
There’s no published weight limit, but there’s no cargo option either, so a pet that doesn’t fit under the seat can’t fly Allegiant at all.
Flying Allegiant with a small dog or cat is mostly a matter of getting the carrier right, because almost everything else follows from it: the fee, the seat you get and what else you can carry on board.
The rules are short, and a few of them are stricter than on bigger airlines, so here is all of it in one place, from the size of the bag to what happens at the gate.
| Rule | What Allegiant allows |
|---|---|
| Pets in the cabin | Domestic dogs and cats only, at least 8 weeks old |
| Fee | $50 per carrier, per flight, non-refundable |
| Soft-sided carrier | Up to 18 x 12 x 11 in, fully closed |
| Hard-sided carrier | Up to 17 x 11 x 10.5 in, fully closed |
| Weight limit | None published: the pet must fit the carrier |
| Pets per carrier | Up to two, if both fit comfortably |
| Carriers per traveler | One per paid traveler |
| Routes | Flights within the 48 contiguous states |
| Cargo | Not available |
| Check-in | With an agent, at least 1 hour before departure |
From Allegiant’s pets page, fees table and contract of carriage, checked 19 October 2026.
Which pets can fly
Allegiant’s contract of carriage accepts only domestic dogs and cats as pets, and only in the cabin, so rabbits, birds and every other animal stay home.
Your pet has to be at least 8 weeks old and must not be ill or in distress, and the contract also asks for an animal that is harmless, non-disruptive and odorless, which gives the crew room to refuse a pet that isn’t coping.
Allegiant doesn’t publish a list of banned breeds, and it doesn’t ask for a health certificate on these domestic flights. What decides everything is whether your pet fits the carrier.
Two pets can share one carrier as long as both fit comfortably inside it, and each paid traveler can bring one carrier. Allegiant’s FAQ also says a child of at least 15 who is flying alone can bring a pet.
The carrier is the whole game
Allegiant’s pets page gives two sizes, both measured with the carrier fully closed: up to 18 inches long, 12 inches wide and 11 inches high for a soft-sided carrier, and up to 17 x 11 x 10.5 inches for a hard-sided one.
Soft-sided carriers are preferred, although hard-sided ones are accepted, and either kind has to be leak-proof, well ventilated and fully closed around your pet.
There is no weight limit. Instead, your pet must fit without touching the sides or poking out, and it must be able to stand up and turn around inside it.
Numbers to ignore
If you’ve read 8 x 14 x 18 inches or a 25 lb limit elsewhere, including on an older version of this page, those figures don’t come from Allegiant, and a carrier bought to them may not match the real limit.
What it costs
The pet fee is $50 per carrier for each flight, and it isn’t refunded. A round trip with one nonstop flight each way costs $100, and two pets sharing one carrier still pay a single fee.
The carrier also counts as one of the two items you can take on board, so you can bring the carrier with either a personal item or a paid carry-on bag, but not both. Anything extra is checked, with the usual bag fees.
For comparison, Southwest charged $125 per pet carrier on mainland US flights when I checked on 19 October 2026, so Allegiant’s fee is $75 lower for each flight.
Allegiant’s optional services fees table lists Pet-in-Cabin at $50.00 per person, per segment, checked 19 October 2026.
Adding your pet to the booking
This is the one part Allegiant doesn’t spell out. Its pets page, contract and FAQ explain the fee and the rules, but none of them says whether you can add Pet-in-Cabin online or have to call.
When I ran a test booking from Las Vegas on 19 October 2026, there was no pet option on the flight or traveler pages, and the extras only come after you enter every passenger’s details.
- Look for Pet-in-Cabin in the extras when you book online, and if you don’t see it, don’t finish the booking assuming you can add it later.
- Call Allegiant Customer Care at (702) 505-8888 to add the pet or confirm how to. A whole ticket bought through the call center carries a $19.99 booking fee per person, per flight.
- Choose your seat carefully: exit rows and the bulkhead aren’t allowed with a pet, and on Boeing aircraft neither are aisle seats.
- Check in with an Allegiant agent at the ticket or gate counter at least one hour before departure, with your pet in its carrier.
At the airport and on the plane
At security, the TSA asks you to take your pet out of the carrier and carry it through the metal detector while the empty carrier goes through the X-ray, so a harness and leash make that minute much calmer.
After that, your pet stays fully inside the carrier, in the airport and on board, and the carrier goes under the seat in front of you for taxi, takeoff and landing.
That’s also where the seat rules bite: exit and bulkhead rows aren’t allowed with a pet, and if you picked an aisle seat on a Boeing aircraft, Allegiant will move you.
Our guide on keeping a dog calm on a flight has ideas for the hours before you leave home.
Where your pet can’t go
Pets fly on flights within the 48 contiguous states, and Allegiant warns that international destinations and US territories don’t accept all pets.
The short summary on Allegiant’s pets page also mentions Puerto Rico, while the rules underneath it only talk about the 48 states, so call before booking a pet on any route outside them.
No cargo option
Allegiant doesn’t carry animals in the cargo hold at all. If your dog is too big for an under-seat carrier, you’ll need another airline or a pet shipper, and our guide to what it costs to ship a dog compares the options.
Service dogs
Allegiant accepts trained service dogs in the cabin free of charge, and only dogs: a service animal is a dog of any breed that is individually trained to do work or perform tasks for a person with a disability.
You can bring up to two, and Allegiant asks for the DOT Service Animal Air Transportation Form at least 48 hours before departure. If you book within 48 hours of the flight, start the online process as soon as you can.
Your dog must stay leashed, harnessed or tethered and under your control, on the floor, under the seat or on your lap, and if it doesn’t fit your foot space you may have to buy a second seat.
Allegiant also requires a current, verifiable rabies vaccination, and it considers dogs in training and on-duty search and rescue or police dogs case by case, as its special needs page explains.
Emotional support animals
Since the DOT’s rule change in January 2021, US airlines don’t have to treat emotional support animals as service animals, and Allegiant’s pages only recognize trained dogs.
That means an emotional support dog or cat flies as an ordinary pet, in a carrier that fits the limits above, for the $50 fee.
Allegiant and Sun Country
Allegiant completed its purchase of Sun Country Airlines on 13 May 2026, but the two still fly as separate airlines, and Allegiant’s FAQ says their booking systems remain separate for now.
Their pet rules differ too: Sun Country charges $75 each way when the pet is booked in advance and caps a flight at six pets, so check which airline is actually selling and flying your ticket.
Questions people ask
How much does Allegiant charge to fly with a pet?
Allegiant charges a non-refundable $50 per pet carrier on each flight, so a round trip with two nonstop flights costs $100. Up to two pets can share that one carrier if they both fit comfortably.
What size pet carrier does Allegiant allow?
A soft-sided carrier can be up to 18 inches long, 12 inches wide and 11 inches high when fully closed. A hard-sided carrier can be up to 17 x 11 x 10.5 inches. Soft-sided carriers are preferred.
Does Allegiant have a weight limit for pets?
No weight limit is published. The rule is about fit: your pet has to stand up and turn around without touching or poking out of the carrier, and the carrier has to go under the seat.
Can my dog fly in cargo on Allegiant?
No. Allegiant doesn’t carry animals in the cargo hold, so a dog that is too big for an under-seat carrier can only fly with Allegiant if it is a trained service dog.
Does Allegiant accept emotional support animals?
Not as service animals. Allegiant only recognizes trained service dogs, so an emotional support dog or cat flies as a pet, in a carrier, for the $50 fee.
Can I fly my pet to Puerto Rico or abroad on Allegiant?
Allegiant’s pet rules are written for flights within the 48 contiguous states, and it says international destinations and US territories don’t accept all pets. Call Allegiant before you book a pet on any other route.
Can a teenager flying alone bring a pet on Allegiant?
Yes. Allegiant’s FAQ says a child who is at least 15 years old and traveling alone can bring a pet on board.
I rewrote this guide in October 2026 and fixed several errors in the old version, including the carrier size, a 25 lb weight limit Allegiant never set, the number of service dogs allowed, a per-flight pet cap it doesn’t publish and an out-of-date Southwest fee.
For other carriers, our airline pet policies A to Z compares the rules side by side.
The Nomad Paws is in memory of Woody, a great traveler and, most of all, the best, kindest and wisest friend I have ever had.
This guide is based on Allegiant’s own pages, its contract of carriage (effective 21 July 2026) and the DOT’s service animal rules, all checked on 19 October 2026. It isn’t legal or veterinary advice, and airlines change their rules, so confirm with Allegiant before you fly. Here is how I make my guides.
