Allegiant Carry-On Rules: How to Avoid Extra Fees!

With low-cost airlines like Allegiant, the fare is only half the story. The things that usually trip people up are (1) assuming an overhead carry-on is included, (2) showing up with a “personal item” that’s too big for the under-seat limit, and (3) waiting until the airport to add bags (that’s typically the most expensive moment to do it).

Below is the simple cheat sheet, then the details.

Allegiant carry-on rules at a glance

If you only read one section, make it this one—these are Allegiant’s current published size limits and the pricing “gotchas” that matter most.

• Free personal item (under the seat): 8″ x 14″ x 18″ (about 20 x 35 x 45 cm)
• Paid carry-on (overhead bin): 10″ x 16″ x 22″ (about 25 x 40 x 55 cm)
• Measurements are exterior: Allegiant’s guidance treats all exterior measurements as counting (wheels/handles/pockets/decorations).
• Fees are route and timing-based: bag pricing varies by segment; it’s generally cheapest to add bags during booking.
• Weight limit: Allegiant does not publish a standard carry-on weight limit, but you still need to be able to safely lift/stow your bag.
• Liquids: for U.S. departures, TSA’s 3-1-1 rule applies.

Allegiant Carry-On Policy

Allegiant allows one personal item onboard at no charge, but they charge for both carry-on and checked bags.  The personal item must fit under the seat in front of you, and the carry-on bag must fit and be stowed in the overhead bin or it will have to be checked.

Allegiant personal item rules (free)

Allegiant includes one personal item at no charge as long as it fits completely under the seat in front of you.

Allegiant personal item size limit

Your personal item must not exceed:

• 8″ x 14″ x 18″ (about 20 x 35 x 45 cm)

Good mental model: small backpack, purse, laptop bag, briefcase, or a small tote that stays “under-seat sized” even when fully packed.

What else can I bring onboard besides my two bags?

Allegiant states passengers may also bring certain small items such as a jacket/coat, small umbrella, food for the flight, and a diaper bag, plus necessary medical/assistive devices.

Allegiant carry-on bag rules (paid)

A carry-on bag on Allegiant is the overhead-bin bag—and it costs extra.

Allegiant carry-on size limit

Your carry-on bag must not exceed:

• 10″ x 16″ x 22″ (about 25 x 40 x 55 cm)

Because Allegiant references exterior measurements, don’t ignore wheels/handles/pockets when you’re measuring at home.

If you want to know the exact cost for bags on your specific flight, go to the Allegiant Baggage Fees Calculator and enter your travel route and date.

On Allegiant, the safest way to avoid surprise costs is to decide up front whether you’ll pay for a carry-on, then price it for your exact route before you fly.

Does Allegiant Have a Weight Limit for Carry-on Bags?

Allegiant does not publish a standard carry-on weight limit in the same way some airlines do.

Practical guidance: if your bag is so heavy that you can’t lift it into the overhead bin without struggling, you are increasing the odds you’ll be asked to check it (or repack at the worst possible moment).

Recommended Carry-On Bag

If I’m bringing an overhead-bin carry-on (instead of traveling personal-item-only), this is the bag I’ve used for years and still recommend: the Travelpro Maxlite 5 Expandable Spinner. It’s lightweight, rolls smoothly, and the internal layout makes it easy to pack without feeling like you’re playing Tetris.

Here are the manufacturer dimensions:

• Overall dimensions (includes wheels and carry handles): 23″ H x 14.5″ W x 9″ D
• Case dimensions (the main body): 21″ H x 14″ W x 9″ D

Allegiant carry-on fees: what to watch out for

Allegiant’s bag fees can be confusing because pricing varies by route and timing. Here’s the framework that holds up:

1. Bags are priced by route and per flight segment. Round-trip itineraries typically mean you pay per direction/segment.
2. Adding bags at booking is typically the cheapest. Allegiant explicitly encourages buying bags when you book.
3. Airport pricing is typically the most expensive. Allegiant publishes an airport bag fee figure (per bag, each way) and directs travelers to check route-specific fees.

If you’re trying to keep costs predictable, add bags (if you need them) during checkout and avoid “I’ll deal with it at the airport.”

Do Allegiant bundles include bags?

Sometimes, yes—but it depends on the bundle and the specific flight.

Two key things to know:

• Bundle inclusions can vary by city-pair/flight.
• Bundles are generally only available at the time of original booking (and you may not be able to upgrade later).

My rule of thumb: during checkout, confirm you see the carry-on icon included (or explicitly added) before you pay.

Allegiant Airlines liquids policy for carry-ons

For U.S. departures, Allegiant points travelers to TSA screening rules for liquids. In practice, this means the standard TSA 3-1-1 rule at the security checkpoint.

TSA 3-1-1 rule (the quick version)

• Containers must be 3.4 oz (100 mL) or less
• All containers must fit in one quart-size clear bag
• One bag per traveler

Exceptions to this rule are certain medications and baby food/child nourishment.

Frequently Asked Questions