What is Southwest's carry-on size limit?

Southwest allows one carry-on bag up to 10×16×24 inches (25×40×61 cm). There is no weight limit on the carry-on bag. You can also bring one personal item that fits under the seat.

Does Southwest charge for checked bags?

No. Southwest's Bags Fly Free policy gives every passenger two free checked bags up to 50 lb each, regardless of fare type, credit card, or loyalty status. This applies to all passengers on all Southwest flights.

Is there a weight limit on Southwest carry-on bags?

No. Southwest does not impose a weight limit on carry-on bags. As long as your bag fits the 10×16×24 inch size limit and you can lift it into the overhead bin yourself, there is no weight restriction.

How does Southwest's bag policy compare to other US airlines?

Southwest is unique — the only major US airline that includes two free checked bags for all passengers. Delta, United, and American charge $35–$45 for the first checked bag and require elite status or credit cards for fee waivers.

Southwest Airlines Carry-On Rules: No Fees, No Limit (2026)

Southwest Airlines operates the most generous baggage policy of any major US airline — and arguably of any major airline in the world. Two free checked bags for every passenger, no carry-on weight limit, and an honest size allowance. If you have never thought about baggage policy when choosing an airline, Southwest's "Bags Fly Free" program is a reason to start. Here is everything you need to know.

Southwest Carry-On Allowance

Southwest permits one carry-on bag per passenger:

Maximum dimensions: 10 × 16 × 24 inches (25 × 40 × 61 cm)
Weight limit: None
Overhead bin: Yes — the carry-on goes in the overhead bin
Additional personal item: Yes, one personal item under the seat

Southwest's carry-on size is expressed differently from other airlines, with the shortest dimension listed first. Rearranged to the conventional longest × width × depth format, this is approximately 24 × 16 × 10 inches — close to, but slightly smaller in depth (10 vs 9 is common, but the 16 in height is larger than typical). This is broadly comparable to the standard 22 × 14 × 9 inch US carry-on used by Delta, United, and American, though Southwest's listed dimensions suggest a more generous size.

In practice, Southwest's overhead bins accommodate standard rolling carry-on luggage without issue. The size limit is less aggressively enforced than the checked bag policy — Southwest's model historically depended on throughput speed, and gate-checking bags slows boarding.

The Personal Item

In addition to the carry-on, every Southwest passenger may bring one personal item:

Examples: Purse, small backpack, laptop bag, diaper bag, briefcase
Requirement: Must fit under the seat in front of you
Size guidance: Southwest does not publish personal item dimensions; under-seat fit is the test

Southwest's personal item policy is standard. The key advantage is that the personal item comes on top of both the carry-on bag and the two free checked bags — Southwest passengers can travel with more than any equivalent passenger on a US competitor.

Bags Fly Free: The Two Free Checked Bags

Southwest's signature policy is simple: every passenger on every Southwest flight gets two free checked bags.

Details

Who qualifies: Every passenger, every time, no conditions
Weight limit per bag: 50 lb (23 kg)
Size limit per bag: 62 linear inches (length + width + height combined)
Overweight bags (50–100 lb): $125 fee
Over 100 lb: Not accepted as checked bags
Oversized bags (over 62 linear inches): $125 fee

There are no exceptions that reduce this benefit. You do not need:

Southwest Rapid Rewards credit card
Southwest elite (A-List or A-List Preferred) status
A specific fare type (Wanna Get Away, Anytime, Business Select — all qualify)
Travel companions on the same reservation to qualify

What This Is Worth

On a single round trip per person, two free checked bags saves:

Compared To	Savings Per Round Trip Per Person
Delta (without card/status)	$70 ($35 × 2 segments)
United (without card/status)	$70
American (without card/status)	$70
Spirit or Frontier	$90–$160 (higher carry-on and checked bag fees)

For a family of four on a round trip, that's $280 in checked bag savings versus a Delta flight without credit card or elite status. This frequently makes Southwest's total cost lower than competitors even when the base fare is nominally higher.

Why Southwest's Policy Exists

Southwest Airlines built its brand on operational simplicity and the middle American traveler. The "Bags Fly Free" policy was formally branded and marketed in 2008, the same year most US carriers began charging for checked bags. It was a deliberate competitive differentiator.

The policy aligns with Southwest's operational model:

Southwest uses a boarding system with no seat assignments (A/B/C boarding groups), which incentivizes early check-in — gate agents know who is on each flight well in advance
Southwest does not fly long-haul international routes (except Mexico, Caribbean, and some Central America) where complex baggage handling is most expensive
Southwest's fleet standardization (primarily Boeing 737 variants) simplifies ground handling

Southwest Carry-On Enforcement

Southwest's carry-on enforcement is comparatively relaxed. The airline uses open seating (no assigned seats), which means boarding speed matters enormously — gate agents do not slow down the process by measuring bags.

What Gets Flagged

Bags that are clearly, significantly oversized — hard-shell suitcases that are full-size checked luggage
Passengers attempting to bring bags that cannot physically fit in the overhead bin
More than one carry-on bag per passenger (strictly enforced — only one carry-on goes in the bin)

Gate-Check Policy

On full flights where overhead space runs short, Southwest gate agents ask passengers to volunteer to gate-check their carry-on. Gate-checked bags on Southwest are free and returned at the jet bridge at the destination — not at baggage claim. Given that everyone has two free checked bags anyway, voluntarily gate-checking a carry-on on Southwest is less disruptive than on airlines where checking a bag costs $35.

A-List and A-List Preferred: Boarding Advantages

Southwest's loyalty program, Rapid Rewards, offers two elite tiers with boarding benefits:

Status	Qualifying Flights	Boarding Group
A-List	25 flights or 35,000 tier qualifying points/year	A Group (guaranteed early boarding)
A-List Preferred	50 flights or 70,000 tier qualifying points/year	A Group (priority within A)

On Southwest, boarding group determines overhead bin access. The A Group boards first, meaning A-List members always have access to overhead bins above any remaining seat. For passengers who check bags routinely (rather than carry on), this matters less — but for carry-on only travelers, A-List status ensures bin space.

EarlyBird Check-In

Southwest also sells "EarlyBird Check-In" as an add-on ($15–$25 per passenger per segment), which automatically checks you in 36 hours before departure and generally places you in the A or early B boarding group. This is less certain than A-List status but improves bin access for occasional Southwest travelers.

Southwest vs Other US Carriers: Full Comparison

Feature	Southwest	Delta	United	American	Spirit
Carry-on included	Yes	Yes (not Basic Economy)	Yes (not Basic Economy)	Yes (not Basic Economy)	Paid add-on
Carry-on weight limit	None	None	None	None	None
Personal item	Yes	Yes	Yes	Yes	Yes (smallest size)
First checked bag	Free	$35 (no card/status)	$35 (no card/status)	$35 (no card/status)	$49+
Second checked bag	Free	$45	$45	$45	$59+
Checked bag weight	50 lb	50 lb	50 lb	50 lb	40 lb

Southwest's advantage is most pronounced in the checked bag comparison. Spirit and Frontier charge for carry-on bags too, making their apparent low-fare savings largely illusory for any traveler with more than a personal item.

International Southwest Flights: Same Rules Apply

Southwest operates international routes to Mexico, the Caribbean (Jamaica, Aruba, Bahamas, etc.), and Central America (Costa Rica, Belize). The Bags Fly Free policy applies on all international Southwest routes — two free checked bags, same as domestic.

Customs and duty: Returning from international destinations, CBP standard rules apply. Southwest does not change its bag policy for international flights, but remember that duty-free purchases and items acquired abroad are subject to US customs declaration requirements.

Tips for Southwest Travel

You do not need to optimize around bags. Unlike every other major US carrier, Southwest's bag policy is already the best available to every passenger. No need for credit card strategy, status management, or carry-on packing to avoid fees.

Book early for early boarding. Rapid Rewards members who check in early get better boarding positions. If you want bin space certainty, buy EarlyBird Check-In or earn A-List status.

Take advantage of the two free bags. Many travelers continue to carry-on only on Southwest out of habit or convenience. But if your trip genuinely benefits from a checked bag, Southwest is the only major US airline where checking bags costs nothing.

Compare total cost, not just fare. When comparing Southwest to Delta or United on the same route, add $70 (round trip, two checked bags) to the competitor's base fare for a fair comparison. Southwest's often-higher base fares frequently cost less in total.

The Bottom Line

Southwest Airlines allows one carry-on (10 × 16 × 24 inches) and one personal item with no weight limit. Every passenger also gets two free checked bags up to 50 lb — the most generous baggage policy of any major US airline, with no credit card or status required. Enforcement is relaxed; gate agents prioritize boarding speed over bag measurement. If you regularly check bags, Southwest is uniquely cost-effective on domestic US travel.