Southwest Carry-On and Personal-Item Size Rules

Know the carry-on measurement

Southwest publishes a carry-on limit of 24 x 16 x 10 inches. The airline says wheels, handles, and attachments count, so measure the outermost points of the packed bag. Use a tape measure across the packed exterior, including wheel housings, handle caps, and anything strapped on. Close expansion zips before comparing the bag with the limit. Southwest Carryon and Personal Item Policy is the primary current reference for the rule described here. Deep Arrival checked the official sources for Southwest Carry-On and Personal-Item Size Rules on September 2, 2026; recheck them after any fare or itinerary change.

Reserve the personal-item role

Southwest permits one personal item in addition to the carry-on. It should fit under the seat ahead and can be a purse, backpack, briefcase, laptop case, or similar compact bag. Underseat space changes by aircraft and seat location. Keep the personal item compact enough to fit without borrowing overhead space intended for the larger bag. The published details in Southwest Contract of Carriage should be rechecked before departure.

Use the larger bag for overhead storage

A roller bag or small suitcase belongs in the overhead bin. Put inflight items in the smaller bag so you do not need to open the bin during boarding. Board with the smaller bag organized for headphones, medication, documents, and chargers. That avoids standing in the aisle searching through the overhead bag after boarding. Southwest Checked Baggage Policy supplies the authoritative limit or procedure used in this section.

Check partner itineraries

Southwest notes that partner-airline guidelines can differ. The airline operating a segment may apply its own cabin dimensions and allowance rules. Look for the operating-carrier label on every segment, not just a Southwest flight number. Recheck after an itinerary change because partner rules can differ materially. Use FAA PackSafe to confirm the current version of this guidance.

Plan for a full cabin

Published dimensions do not guarantee bin space. Keep critical items in the personal item in case a cabin bag has to be checked at the gate. Have a gate-check plan before boarding begins. Put valuables and travel documents in the personal item, and keep a small pouch ready for batteries and chargers.

Treat the sizer as decisive

A bag marketed as a carry-on can still exceed the Southwest sizer when fully packed. Check the actual exterior instead of relying on a product label. Try the bag in a sizer while it is fully packed. Compression straps can help only if the final exterior fits naturally and no rigid item presses outward.

Pack batteries correctly

FAA guidance requires power banks and spare lithium batteries to remain with the passenger in the cabin. Do not leave them in a bag that becomes gate-checked. If a cabin bag is collected at the gate, remove spare cells and power banks before it enters the hold. Keep them with you for the entire flight.

Recheck before departure

Southwest can update baggage guidance and a flight can have partner or aircraft differences. Read the current policy on the day of travel. Review the policy during check-in and inspect the flight details for an operator or aircraft update. A prior trip is not a substitute for the current booking.