Southwest Airlines Personal Item

Southwest publishes no length or width numbers for a personal item. The rule is one sentence. It has to fit under the seat in front of you.

That single line covers every Southwest fare. A Southwest carry-on and personal item allowance never shrinks on a cheaper ticket. Some low-cost rivals cannot say the same.

Both bags travel free every time you fly. That fits the pattern across the airline’s full baggage rules.

What Southwest counts as a personal item

Southwest’s own carry-on and personal item policy lists a purse, a briefcase, a laptop case, a backpack and a small camera. All five count as personal items.

A pillow or blanket makes the list too. Neither one counts toward the limit, which most carriers do not bother to say.

The carry-on bag gets a hard number instead: 24 by 16 by 10 inches, or 61 by 41 by 25 cm. Wheels and handles count toward that box.

So a Southwest carry-on and personal item pairing is really one measured bag. The other bag is judged only by whether it slides under the seat ahead.

Why there is no tape measure for the personal item

Most underseat space on a Southwest 737 runs close to 17 by 13 by 8 inches. The exact figure shifts by seat row.

A life vest pouch or an entertainment box can eat into that space on some rows. Southwest has never published a seat by seat chart the way some carriers do.

Gate agents and flight attendants use their own judgment instead of a printed sizer. That differs from a budget carrier that puts a metal cage at the gate. There, every bag gets measured against it.

If you want a number to pack to, aim under 17 by 13 by 8 inches. That size clears nearly every seat in the fleet.

The personal item is free on every Southwest fare

This is where the Southwest carry-on and personal item allowance earns its reputation. Basic, Choice, Choice Preferred, Choice Extra and Business Select all carry the same carry-on and personal item allowance.

None of those fares charge for either bag. That sets Southwest apart from the ultra low-cost carriers. Their cheapest fare often includes only the personal item.

The airline’s checked bag fees arrived in 2025 when Southwest ended its long standing free checked bag policy. Those charges apply only to the hold, not to what you carry aboard.

What happens when a personal item does not fit

Southwest’s own guidance is direct. If a bag looks too big, check it at the ticket counter before heading to the gate.

The airline’s published pages do not list a specific gate fee for an oversized personal item, unlike several ULCCs. Southwest’s checked bag charges apply to the hold. They do not apply to a personal item pulled aside at boarding.

A bag pulled at the gate for being oversized is typically checked through to your destination. It rides free rather than getting billed as a separate charge.

If you are flying with something borderline, measure it at home before you leave. That beats finding out at the jet bridge. The site’s guide to measuring carry-on luggage covers the method.

Bags that fit under a Southwest seat

Travelpro Maxlite 5 underseat rolling tote slides under an airline seat while still rolling through the terminal. That matters on a Southwest connection with a full concourse to walk.

Baggallini Avenue tote is a soft laptop tote with a trolley sleeve that clips over a rolling carry-on. Customer reviews commonly mention that it compresses easily when the underseat gap runs tight.

Matein travel laptop backpack is one of the most reviewed personal item backpacks sold. According to the manufacturer’s specifications, it measures small enough for most domestic seats. Southwest’s 737s are among them.

A personal item and a carry-on are two separate allowances, not one bag split in half. Pack both to their real limits rather than overstuffing one. That keeps a Southwest carry-on and personal item combination clear of a gate check.

The full carry-on picture on this airline, including the 24 by 16 by 10 inch box, lives on the Southwest carry-on size guide. The site’s size checker tool settles any doubt about a borderline bag before you fly.

The bottom line

Southwest gives every fare the same free personal item and the same free carry-on. Only the carry-on gets a hard number.

Pack the personal item to fit comfortably under a coach seat rather than to a number nobody publishes. Do that and you will rarely have a problem at the gate.

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