Southwest Airlines Carry On Bag Policy Rules and Sizes

Southwest Airlines Carry On Bag Policy Guide

Whether you are packing days in advance or staring at your suitcase on the bedroom floor hours before your flight, navigating the southwest airlines carry on bag policy can be stressful. You need to know exactly what fits in the overhead bin, what fits under the seat, and how to pack for strict event venue rules once you land.

Southwest Airlines allows one carry-on bag (up to 24 x 16 x 10 inches) and one personal item (up to 16.25 x 13.5 x 8 inches) per passenger. While your main luggage does not need to be clear, your carry-on toiletries must follow the strict TSA 3-1-1 clear bag policy for liquids. The safest bag choice is a flexible, soft-sided underseat backpack paired with a standard two-wheel roller bag. If you are ever unsure if your bag will fit, check it at the ticket counter-Southwest is famous for allowing two free checked bags.

How We Check This Policy

BagPolicyGuide prioritizes official airline tariffs, TSA screening procedures, and FAA safety guidelines. We cross-reference these official rules with passenger reports on how gate agents actively enforce sizer boxes. We separate strict, confirmed sizing limits from the unpredictable nature of crowded flights, giving you the safest packing recommendations.

Official Bag Policy Overview

Southwest Airlines employs a standard "1 + 1" bag rule. Every ticketed passenger is allowed to bring one carry-on bag and one smaller personal item into the cabin free of charge.

Unlike some strict basic economy fares, Southwest is quite generous with its sizing. The maximum carry-on bag size is 24 x 16 x 10 inches. There is no official weight limit for carry-on luggage on Southwest flights. The only rule is that you must be physically able to lift your bag into the overhead bin without assistance.

What Makes This Bag Policy Different

Two major factors make packing for a Southwest flight unique.

First, Southwest does not assign seats. Passengers board in Groups A, B, and C. By the time Group C boards, the overhead bins are frequently full. Second, Southwest is one of the only U.S. airlines that still offers two free checked bags. If you are forced to gate-check your carry-on because the bins are full, or because your bag is an inch too wide, Southwest does not hit you with a massive penalty fee at the gate. This is drastically different from rigid budget carriers (or strict legacy basic economy fares, which you can read about in our United Airlines Checked Bag Rules guide).

Allowed Bags and Size Limits

Clear bags

While Southwest doesn't require clear luggage, your liquids must be packed in a clear, quart-sized, zip-top bag to comply with the TSA 3-1-1 rule. If you are traveling to a stadium or festival, you can bring an approved 12 x 6 x 12 inch clear stadium bag as your personal item, or pack it flat inside your carry-on.

Small clutches and wallets

Small purses, fanny packs, clutches, and wallets are permitted, but they must be counted. A fanny pack worn across your chest is viewed by gate agents as a personal item. If you already have a backpack and a roller bag, you must stuff the clutch or fanny pack into one of your larger bags before boarding.

Backpacks, purses, and crossbody bags

Backpacks are universally allowed but fall into two categories based on size:

• If your backpack is 16.25 x 13.5 x 8 inches or smaller, it is your personal item and must slide completely under the seat in front of you.
• If your backpack is larger than those dimensions (up to 24 x 16 x 10 inches), it is your carry-on and must go in the overhead bin.

Diaper bags, medical bags, and ADA exceptions

FAA-approved assistive devices (like CPAP machines, portable oxygen concentrators, and mobility aids) do not count toward your carry-on limit. However, family gear is treated differently. Diaper bags are not exempt on Southwest and will count as either your carry-on or personal item. For detailed family packing strategies, read our Southwest Diaper Bag Policy Rules guide.

Category-specific bags if relevant

If you are flying to a winter destination, you may be carrying oversized gear. While small sports equipment can occasionally fit in the overhead bins, skis and snowboards require special handling. Check our Southwest Ski Bag Policy Guide for exact winter sports limits.

Prohibited Bags and Items

Certain items are strictly forbidden in the aircraft cabin by FAA and TSA regulations. Do not pack the following in your carry-on or personal item:

• Smart luggage with non-removable lithium-ion batteries
• Self-balancing boards (hoverboards, electric skateboards)
• Liquids, gels, or aerosols larger than 3.4 ounces (100ml)
• Sharp objects including pocket knives and scissors longer than 4 inches
• Flammable items including lighter fluid and fireworks

How Security Screening Works

Because airline policies intersect directly with TSA rules, your bag will go through rigorous X-ray screening.

1. Preparation: Have your ID and boarding pass ready at the podium.
2. The Belt: You will place your carry-on and personal item on the conveyor belt.
3. Electronics: Unless you have TSA PreCheck, you must remove laptops, tablets, and large gaming consoles from your bags and place them in separate bins.
4. Liquids: Your clear, quart-sized 3-1-1 bag must be easily accessible for visual inspection.
5. The Gate Sizer: After clearing TSA, you will proceed to your gate. If a gate agent believes your carry-on looks oversized, they will ask you to drop it into a metal sizer box before you scan your ticket.

Packing Strategy for Faster Entry

The safest way to breeze through both TSA and the boarding process is to use the Modular Flight-to-Venue Packing Method.

First, choose a base personal item (like a soft backpack) that comfortably fits the 16.25 x 13.5 x 8 underseat limit. Pack only your absolute essentials here: passport, medication, phone, and wallet. Second, organize small tech cords into mesh pouches so they don't look like a chaotic tangle on the X-ray scanner. Keep your clear TSA liquids bag right at the top zipper of your backpack so you can grab it in two seconds. Finally, if your carry-on roller bag is slightly bulky, use packing cubes to compress soft clothing, ensuring the bag does not bulge beyond the 10-inch depth limit.

Security Check Anxiety Tips

Nothing causes more airport anxiety than being pulled aside in the security line or at the boarding gate. Prevent this by testing your bag at home with a physical tape measure. Measure from the floor to the very top of the unextended handle. Wheels count!

If you are boarding in Group C, accept the high probability that you will need to gate-check your carry-on bag. Mentally prepare for this by making sure your laptop and medications are already in your underseat bag. If a gate agent asks you to check your roller bag, you can simply hand it over without scrambling to dig your laptop out in the middle of a crowded jet bridge.

Category-Specific Packing Tips

Many travelers fly Southwest specifically to attend major events like NFL games, arena concerts, or multi-day music festivals. These venues strictly enforce their own clear bag policies (typically a 12 x 6 x 12 inch limit). Do not bring a large, non-compliant opaque purse on the airplane if you plan to head straight to the stadium from the airport. Instead, pack your empty 12 x 6 x 12 clear stadium tote completely flat at the bottom of your Southwest carry-on. When you land, transfer your wallet, phone, and keys into the clear bag, leave your roller bag at the hotel, and proceed smoothly through venue security.

Before You Go Checklist

• Check your roller bag dimensions with a physical tape measure (max 24x16x10 inches).
• Test that your personal item squishes to 16.25x13.5x8 inches.
• Check that all liquid containers are 3.4 oz or smaller.
• Organize all liquids into a single clear, quart-sized zip bag.
• Tuck loose items (fanny packs, neck pouches) into your primary personal item.
• Place your laptop or tablet in an easily accessible external sleeve.
• Pack a flat, clear stadium bag in your luggage if attending an event.
• Set an alarm to check in exactly 24 hours before your flight.
• Remove any lithium-ion power banks from checked luggage or smart bags.

Frequently Asked Questions

Is a clear bag required for Southwest Airlines?

No, your main luggage and backpacks do not need to be clear. However, any liquids packed in your carry-on must be placed in a clear, quart-sized zip-top bag to pass through TSA security.

What are the exact dimensions for a Southwest personal item?

A personal item on Southwest must not exceed 16.25 x 13.5 x 8 inches so it can safely fit entirely under the seat in front of you.

Does a backpack count as a personal item or a carry-on?

It depends entirely on its size. A small backpack that fits under the seat counts as a personal item. A large hiking or travel backpack that must go in the overhead bin counts as your carry-on.

Are diaper bags free on Southwest?

No. Unlike medical equipment, a diaper bag counts toward your allowance. It will be classified as either your personal item or your carry-on bag depending on its size.

Does a CPAP machine count against my bag limit?

No. Medical devices such as CPAP machines, breast pumps, and portable oxygen concentrators are exempt and do not count toward your one carry-on and one personal item limit.

Is there a weight limit for carry-on bags?

Southwest has no official maximum weight limit for carry-on luggage. You only need to be able to physically lift your bag into the overhead bin by yourself.

What happens if my carry-on bag is too big at the gate?

If your bag cannot fit in the sizer box or if overhead bins are full, the gate agent will require you to gate-check it to your final destination.

Does Southwest charge for gate-checked bags?

Typically, no. Because Southwest allows two free checked bags per passenger, gate-checking your carry-on usually costs nothing unless you have already checked two large suitcases.

Can I bring my own food on the airplane?

Yes, you can bring solid food (like sandwiches or chips) through TSA and onto the plane. However, liquids, gels, or spreadable foods (like peanut butter or yogurt) must follow the 3.4 oz limit.

Conclusion

Southwest Airlines offers one of the most generous baggage policies in the industry, making packing for your trip surprisingly easy if you follow the rules. Ensure your carry-on is no larger than 24 x 16 x 10 inches and your personal item fits easily under the seat. By prepping your clear TSA liquids bag and checking your boarding position early, you can avoid gate delays and travel with confidence.

Bag policies can change by event, venue, season, and security team. Always confirm the latest rules on the official venue, park, team, festival, organizer, or event website before you leave. Information is checked for 2026 where available, but official sources should always be treated as the final authority.