Southwest Personal Item & Carry-On Rules 2026: What's Free

Every Southwest fare in 2026 — including the cheapest Basic ticket — comes with a free carry-on of 24 × 16 × 10 in and a free personal item that has to fit under the seat in front of you. That's the intact half of the policy, verified against Southwest's official carry-on page in July 2026.

The other half is history. Checked bags stopped flying free on 28 May 2025 after 54 years, and for bookings on or after 9 Apr 2026 they run about $45 for the first and $55 for the second. Oversize items of 62–80 linear inches add roughly $200 on top, and the standard checked weight limit is 50 lb (23 kg).

This page is our canonical Southwest hub: the sizes, the fee history with dates, the 2026 boarding chaos, and a dated change log at the bottom. When a rule moves, this is where it moves first.

Southwest publishes no dimensions for the personal item. The entire official rule is one sentence: it must fit under the seat in front of you. No inches, no weight limit, no sizer frame — the seat is the sizer. Southwest's own examples: a purse, briefcase, laptop case, backpack, pillow, blanket or small camera.

The numbers you see elsewhere are unofficial. Third-party guides commonly cite roughly 16.25 × 13.5 × 8 in — described as the tightest under-seat space across Southwest's 737 fleet — and older guides quote 18.5 × 13.5 × 8.5 in. Neither figure appears on the current policy page, so treat them as a conservative envelope, not as law.

Our compression backpack measures 15.7 × 11.8 × 7.9 in (40 × 30 × 20 cm, about 24 litres) — inside even the tighter unofficial figure on every side, and comfortably under the seat. Nothing to argue about, because there's no number to argue with.

No. "Bags fly free" ended on 28 May 2025, after 54 years. Southwest had literally trademarked the slogan — registered ®, the works — and the trademark outlived the promise. The push came from activist investor Elliott Management, which took a roughly 10% stake and five board seats in October 2024, flagged bag fees as untapped revenue, and began cashing out its stake once the fees landed. The fees stayed; the investor is already heading for the exit.

For bookings on or after 9 Apr 2026, the first checked bag runs about $45 and the second about $55 — up $10 from the launch prices. The arithmetic stings: a Basic-fare couple checking two bags round trip now pays roughly $200. Fourteen months earlier, $0.

Some exceptions survive: Choice Extra fares include two free checked bags, A-List Preferred gets two, A-List one, Rapid Rewards cardholders one, and active-duty military check free. Everyone else has a cheaper option — the under-seat bag, still $0.

The Southwest carry-on limit is 24 × 16 × 10 in (61 × 41 × 25 cm), wheels and handles included — free on every fare. That's the most generous published carry-on of any major US airline: the de-facto standard elsewhere is 22 × 14 × 9 in, which makes Southwest's roughly 38% more volume.

Metal sizer frames for the 24 × 16 × 10 in bag do sit at Southwest gates, and 2026 is the year US airlines industry-wide got serious about sizers and automated scanners — with wheels, handles and attachments explicitly counted. A pet carrier, for the record, counts as either your carry-on or your personal item, not as a bonus.

One cloud on the horizon: Southwest is reportedly weighing removing overhead-bin access from Basic fares. The airline's on-record answer is that it has no such plans, and nothing has changed as of July 2026 — but if it ever ships, the free under-seat personal item becomes the last free bag on a Basic ticket. Worth owning a good one.

Historically the most relaxed of the US majors — and structurally so, because there are no personal-item dimensions to enforce. No number, no frame, no tape measure. Gate agents watch one thing: whether the bag genuinely goes under the seat. If it slides under, that's the whole test.

That is not an invitation to bring a duffel the size of a labrador. Industry-wide, 2026 is the year US carriers started actively using sizers and automated scanners, and Southwest's carry-on rule already counts wheels, handles and attachments. The direction of travel is stricter, not looser.

The only strategy that works in any policy weather is a bag that fits by arithmetic. Ours measures 15.7 × 11.8 × 7.9 in packed — hardshell, so the packed size and the published size are the same number — and "does it fit under the seat" stops being a judgement call. It just fits.

On 27 Jan 2026 Southwest replaced open seating with assigned seats and boarding Groups 1–8 — and immediately started a daily overhead-bin squeeze. The old open-seating scramble spread bags through the cabin; now forward bins fill early, and later groups routinely watch their carry-ons get gate-checked. Forbes ran the headline that Southwest's boarding is now worse than the airlines it copied, and Southwest is publicly tweaking the order after the backlash.

The consolation is very Southwest: gate-checking costs nothing, no matter why it happens. Free, though, is not the same as convenient: the bag rides in the hold and waits for you at baggage claim, so your flight ends at a carousel — laptop, meds and all out of reach since boarding.

An under-seat bag opts out of the entire game. It boards in any group, needs no bin, and lands with you. The 2026 risk on Southwest isn't a sizer — it's bin space, and the personal item is exempt.

Yes — every fare includes both: one carry-on up to 24 × 16 × 10 in for the bin, and one personal item for under the seat. A backpack rides free as the personal item; Southwest names backpacks explicitly in its own examples, alongside purses, laptop cases, pillows and blankets.

The smart split in 2026: things you can live without for a flight go in the carry-on — the gate-check candidate — and things you can't, like the laptop, meds, chargers and a change of clothes, go in the under-seat backpack. If the bins fill and the carry-on gets checked to baggage claim, you lose nothing you'll miss mid-flight.

For trips up to a week, plenty of travelers skip the bin entirely: a compression backpack presses seven days of clothes into 15.7 × 11.8 × 7.9 in, and the whole trip flies at your feet. One bag, zero fees, zero boarding-group anxiety.

The dated record the rest of this site quotes — one canonical wording per change.

Oct 2024 — activist investor Elliott Management wins five board seats after building a ~10% stake; bag fees flagged as untapped revenue. 11 Mar 2025 — Southwest announces the end of "Bags fly free". 28 May 2025 — free checked bags end after 54 years: ~$35 first / ~$45 second for new bookings, and the Basic fare debuts. Carry-on and personal item stay free on all fares.

27 Jan 2026 — assigned seating and boarding Groups 1–8 replace open seating; overhead-bin congestion follows. 9 Apr 2026 — checked-bag fees rise $10 to ~$45 / ~$55 for new bookings. 2026, reported — Southwest is said to be studying removing overhead-bin access from Basic fares; the airline says it has no such plans. Not enacted, tracked here. July 2026 — every figure re-verified against Southwest's official carry-on policy page.