Spirit Airlines Pet Policy (In-Cabin): The Complete 2026 Guide

Spirit Airlines charges roughly $125 each way (non-refundable) to bring a small dog, cat, domestic rabbit, or household bird into the cabin on a domestic flight. Your pet must travel in a soft-sided carrier no larger than about 18 x 14 x 9 inches, stay inside it the whole flight, and the pet plus carrier together must not exceed roughly 40 pounds. Spirit does not offer cargo. Confirm current fees and rules on Spirit's official pet page before booking.

The short version: what Spirit allows in the cabin

Spirit is a budget carrier that allows pets only in the passenger cabin. There is no checked-pet or cargo program, so if your animal is too big to fit under the seat in a carrier, Spirit is not an option and you will need a different airline (see our guide to airline pet policies) or a ground transport service. According to Spirit's traveling with pets guidance, the in-cabin program covers small domestic animals on most domestic routes.

Here is what Spirit permits in the cabin on domestic flights, per the airline's published policy. Always confirm the current list directly with Spirit before you book, because airline pet rules change without much notice.

• Small dogs that fit comfortably in an under-seat carrier.
• Cats.
• Domestic rabbits.
• Small household birds on domestic flights.
• Animals must be at least 8 weeks old to fly.

What is not allowed: any pet that cannot fit in a carrier under the seat, pets in cargo (Spirit has no cargo hold pet service), and pets seated in first-class style premium seats or exit rows. Service animals are handled under a separate Department of Transportation framework and are not the focus of this guide.

How much does it cost to fly a pet on Spirit?

The in-cabin pet fee on Spirit is roughly $125 each way, charged per direction and non-refundable, according to Spirit's published pet policy. That means a round trip runs about $250 in pet fees alone, on top of your own ticket and any bag fees. Treat $125 as an approximate figure and confirm the current amount on Spirit's official pet page before booking, since low-cost carriers adjust ancillary fees frequently.

A few cost notes worth knowing. The pet fee is charged per passenger carrier, not per animal, so if you put two small pets in one approved carrier (more on that below) you still pay one fee for that carrier. The fee is separate from, and in addition to, any carry-on or personal-item bag charges. And because Spirit prices nearly everything as an add-on, the cheapest-looking base fare can end up middling once the pet fee is included, so compare the all-in total against other carriers rather than the headline fare.

If you are weighing the in-cabin route against shipping a larger dog, our breakdown of pet cargo versus in-cabin transport walks through when each makes sense, and our guide to how much pet transport costs puts airline fees in context against ground and door-to-door options.

Carrier size, weight, and the under-seat rule

The single biggest reason pets get turned away at the gate is a carrier that does not fit. Spirit's published dimensions for a soft-sided pet carrier are approximately 18 inches long by 14 inches wide by 9 inches high, and the combined weight of the pet plus the carrier should not exceed about 40 pounds, per Spirit's policy. The carrier must fit fully under the seat in front of you for the entire flight. Confirm the exact current limits with Spirit before buying a carrier, as dimensions can differ slightly by aircraft.

Soft-sided carriers are recommended because they flex into the under-seat space better than a rigid crate. Your pet should be able to stand up, turn around, and lie down comfortably inside. If your dog is on the edge of the size limit, measure the animal standing, not curled up, and choose a carrier that gives genuine room rather than one that technically meets the numbers but leaves the dog cramped.

Picking the right bag matters. Our guide to the best airline-approved dog carriers covers soft-sided models that hold their shape under a seat, and if you are deciding between a soft carrier and a hard crate for a longer journey, see how to choose a pet transport crate.

One carrier per passenger, and how many pets fly per flight

Spirit allows one pet carrier per paying passenger. Inside that single carrier you may bring up to two pets, provided both fit comfortably and the combined weight still meets the under-seat and 40-pound guidance, according to the airline's policy. Two cats or two small dogs of the same household is the typical use case.

Spirit also caps the number of pet containers per flight at roughly six. That is a hard ceiling on a first-come, first-served basis, so the seats with pets can fill up well before departure. Book your pet on as early as possible, and do not assume a slot is available just because there are open seats. Call Spirit or add the pet during booking to lock in the container slot rather than showing up and hoping.

Seating restrictions also apply. Pets are not permitted in Spirit's premium Big Front Seat or in exit rows, since those areas either lack a standard under-seat space or are reserved for passengers who can assist in an evacuation. Pick a standard seat with full under-seat clearance when you book.

How to book a pet on Spirit, step by step

Because pet slots are limited and the fee is charged separately, the booking sequence matters. Here is the order that avoids surprises at the airport.

1. Confirm eligibility first. Verify your pet's type, age (at least 8 weeks), and that it fits an under-seat carrier within the size and weight limits.
2. Book a route that allows pets. Spirit's pet program is for domestic in-cabin travel; confirm any international restrictions before assuming you can fly your pet abroad.
3. Reserve the pet during booking or call Spirit. Add the pet as early as possible because of the roughly six-container-per-flight cap.
4. Choose a standard seat, not a Big Front Seat or exit row.
5. Pay the pet fee (about $125 each way, non-refundable) and keep the confirmation.
6. Confirm current rules again 24-48 hours before travel on Spirit's official pet page, since policies and fees can change.

BringFido's airline pet policy directory is a useful secondary cross-check, but Spirit.com is the authoritative source for fees and dimensions. When the two disagree, trust the airline's own page.

Day-of-travel airport tips

A smooth pet flight is mostly about preparation before you reach the gate. These tips reduce the chance of a stressed animal or a last-minute denial.

• Arrive early. Give yourself extra time to check in the pet, since pet bookings often require an agent rather than a kiosk.
• Use the relief area before security. Most airports have a designated pet relief area; let your dog use it before you go through the checkpoint.
• At TSA, your pet comes out of the carrier. You carry the animal through the metal detector while the empty carrier goes through the X-ray. Use a harness and leash so the pet cannot bolt.
• Skip a big pre-flight meal. A light meal a few hours ahead and modest water reduces accidents and nausea. Line the carrier with an absorbent pad.
• Keep the pet in the carrier on board. Spirit requires the animal to stay inside the carrier throughout the flight, except in designated relief areas. Do not open the carrier at your seat.
• Bring documentation. Carry proof of vaccinations even on domestic routes; some destinations or connecting requirements call for it.

Spirit vs Frontier vs Allegiant: budget-carrier pet fees

The three big ultra-low-cost US carriers all offer in-cabin pets only, but their per-segment fees differ enough to change which is cheapest for your trip. The figures below are approximate and based on each airline's published policy; confirm current fees directly with each airline before booking, since these change often.

Read the table by total segments, not by trip. A "per segment" fee is charged on each leg, so a one-stop itinerary can cost two fees each way. On a simple nonstop round trip, Allegiant at roughly $50 per segment tends to be cheapest, Frontier sits in the middle near $99, and Spirit at about $125 each way is the priciest of the three but is still far below the in-cabin fees at most full-service carriers. For deeper looks at the alternatives, see our guides to Frontier's pet policy and Allegiant's pet policy.

If price is your only concern, also weigh the route map and reliability, not just the fee. A cheaper pet fee on an inconvenient connection can mean more segments, more total fees, and more stress on the animal. For the bigger picture across carriers and methods, our cheapest way to transport a pet guide ranks every option by cost.

Who Spirit suits, and who should look elsewhere

Spirit works well if you have a genuinely small pet, you are flying a domestic route Spirit serves, you book the pet slot early, and you have priced the all-in cost rather than just the base fare. For a single small dog or cat on a nonstop domestic hop, it is a reasonable budget choice.

Look elsewhere if your dog is too large for an under-seat carrier, since Spirit has no cargo program and a 40-pound combined ceiling. Medium and large dogs need a carrier that can be checked or a ground service. If you are flying internationally, Spirit's pet program is built around domestic travel, so confirm restrictions carefully and budget time for destination import requirements. For larger animals or longer hauls, compare a full-service carrier or professional ground transport using the cost guides linked above.

How we sourced this

The fees, carrier dimensions, weight limits, eligible animals, and per-flight container caps in this guide are drawn from Spirit Airlines' published "traveling with pets" policy on Spirit.com, cross-checked against BringFido's airline pet policy directory. Comparison fees for Frontier and Allegiant come from each airline's own published pet policy. Because ultra-low-cost carriers adjust ancillary fees and rules frequently, every figure here is approximate and dated to mid-2026. Always confirm the current fee, carrier size, and any international restriction directly with the airline before you book.