Southwest vs Frontier 2026: Southwest Wins If You Bring a Bag

Fees, policies, and figures in this comparison reflect what we verified as of Oct 2026 and can change afterward. Our live tools and the data behind them are re-verified more often than the written comparison.

Southwest and Frontier compete on hundreds of domestic routes but sell fundamentally different products. Southwest bundles a carry-on, free changes, and loyalty point earning into every fare. Frontier sells a bare seat and charges for everything else. On paper, Frontier’s base fare is almost always lower. In practice, the total trip cost depends entirely on whether you need a bag.

This distinction used to be sharper when Southwest offered two free checked bags. That policy ended in May 2025. Southwest now charges $45 for the first checked bag and $55 for the second. But Southwest still includes a carry-on on every fare, and Frontier still charges extra to put a bag in the overhead bin. For the traveler who flies with a roller bag, Southwest’s bundled approach saves Frontier’s full carry-on fee on every flight before you compare fare prices.

For the minimalist traveler who flies with a backpack that fits under the seat, Frontier is genuinely cheaper. If that is you, Frontier’s base fare plus zero add-ons is the lowest total cost in US aviation. For everyone else, add the carry-on fee to Frontier’s fare, compare it to Southwest’s all-in price, and you will usually find Southwest is the same price or less.

What We Looked For

• Total trip cost, not base fare, because ULCC pricing is meaningless without add-on math
• Carry-on policies, the single biggest cost difference between these two airlines
• Reliability, where the gap is large and clear
• Seat comfort, including what each airline does and does not publish about seat pitch
• Loyalty programs, Companion Pass versus GoWild Pass for frequent travelers
• Route overlap, where both airlines compete on the same domestic corridors

Which airline charges less for bags, Southwest or Frontier?

Southwest includes a free carry-on on every fare. Frontier charges extra for one, making Southwest cheaper for any traveler who brings a bag.

This is the section that determines which airline is cheaper for your specific trip.

Carry-on. Southwest includes a carry-on (24x16x10 inches, or 61x40.6x25.4 cm) on every fare. No fee, no bundle required. Frontier charges for a carry-on (also 24x16x10 inches) at a dynamic price, cheapest when added at booking. The price rises at check-in, at the counter, and at the gate. Frontier also enforces a 35-pound (16 kg) carry-on weight limit with scales at the gate. Southwest publishes no carry-on weight limit.

Personal item. Southwest publishes no personal item dimensions; the item just has to fit under the seat in front of you. Frontier’s limit is 18x14x8 inches (45.7x35.6x20.3 cm). Frontier enforces its sizer strictly, so if your bag does not fit the box, you pay the carry-on fee at the gate.

Checked bags. Southwest charges $45 for the first checked bag and $55 for the second (tickets booked from April 9, 2026), with a 50-pound (23 kg) weight cap. Frontier uses fully dynamic pricing with no flat published fee, cheaper at booking and more at check-in or the airport. Frontier’s standard checked bag cap is lower at 40 pounds (18 kg), and bags from 41 to 50 pounds incur a $75 overweight fee. Southwest’s flat rate is comparable or cheaper depending on when you buy.

The math on a round trip with one carry-on:

Frontier’s base fare is usually lower, and Southwest’s includes the carry-on. Frontier stays cheaper only if its carry-on costs less than the fare gap on your route, each way. Check Frontier’s Bag Price Checker for the real number before you book.

The breakeven point shifts when you fly personal-item-only. With no carry-on to buy, the traveler who packs light keeps the whole fare gap. That is real money.

For details on your specific bag, use our carry-on size checker or see our guide to avoiding checked bag fees.

Winner: carry-on inclusion

Southwest / free on all fares vs a paid add-on on Frontier Basic

Winner: carry-on weight policy

Southwest / no published weight limit vs 35 lb enforced

Winner: checked bag fees

Southwest / $45 flat vs Frontier's dynamic pricing

Winner: personal-item-only travel

Frontier / lower base fares when no extras are needed

Is Southwest or Frontier more reliable?

Southwest is significantly more reliable, with a 77.04 percent on-time rate and a 0.85 percent cancellation rate versus a much weaker on-time record and a 1.77 percent cancellation rate for Frontier.

Southwest is dramatically more reliable.

Southwest’s 2025 on-time arrival rate was 77.04 percent (Cirium full-year 2025) with a 0.85 percent cancellation rate (US DOT full-year 2025), one of the lowest among major US carriers.

Frontier was the most-delayed major US airline in 2025, last of 10 on on-time arrivals (US DOT full-year 2025). Its cancellation rate was 1.77 percent (US DOT).

The reliability gap is wide, and Frontier’s cancellation rate (1.77 percent) ran more than double Southwest’s (0.85 percent). Over 20 flights a year, that is a real difference in how often your trip gets disrupted.

Frontier’s lower flight frequency on many routes (often just one or two daily departures versus Southwest’s three to five) makes a cancellation more painful. If your Frontier flight cancels, rebooking options on the same day are limited. Southwest’s higher frequency provides more same-day alternatives.

Winner: on-time arrivals

Southwest / 77.04% vs Frontier, among the most-delayed in 2025

Winner: cancellations

Southwest / 0.85% vs 1.77% (US DOT 2025)

Winner: rebooking options after disruption

Southwest / more daily frequencies on shared routes

Does Southwest or Frontier have more legroom?

Neither airline publishes a standard seat pitch: Southwest says its Extra Legroom seats add three to five inches over Standard, and Frontier says only that its UpFront Plus and Premium seats come with extra legroom.

Neither airline is luxurious, and neither prints the number that would settle this.

Standard economy pitch. Southwest publishes no pitch figure for Standard seats on its all-737 fleet. Frontier’s seating page says its Standard seats “come with standard legroom and space”, with no inch figure for its all-Airbus A320 family fleet. Check the seat map for your flight if an inch matters to you.

Extra legroom. Southwest’s Extra Legroom rows (introduced with assigned seating in January 2026) give three to five more inches than Standard: 5 on the 737-700, 3 on the 737-800 and MAX 8. Frontier’s Premium seats and the top-tier UpFront Plus rows (with a guaranteed empty middle seat) are sold as extra legroom, but Frontier gives no figure. Both are paid upgrades, and Frontier’s sit on top of an already fee-laden base fare.

Seat width. Southwest’s 737 seats are approximately 17 to 17.5 inches (43 to 44 cm) wide. Frontier’s A320 seats are approximately 17.8 inches (45 cm). Marginal advantage to Frontier on width.

Wi-Fi. Southwest charges for Wi-Fi but offers free streaming entertainment through the app. Frontier offers Wi-Fi for purchase and free on-demand entertainment through the Frontier app. Neither provides free fleet-wide Wi-Fi.

Entertainment. Neither airline has seatback screens. Both rely on streaming through their respective apps. Southwest offers free live TV through the app. Frontier’s streaming library is more limited.

Winner: standard legroom

Not published / neither airline publishes a standard pitch

Winner: extra legroom top-end

Not published / Southwest: 3 to 5 in over Standard; Frontier gives no figure

Winner: seat width

Frontier / 17.8" vs 17-17.5", marginal

Winner: free entertainment

Southwest / free live TV via app

Does Southwest or Frontier fly to more destinations?

Both serve roughly the same number of places (121 Southwest airports vs approximately 120 Frontier destinations), but Southwest offers more daily frequencies and flies to Hawaii, which Frontier does not.

Both airlines cover similar domestic territory but with different operating models.

Southwest serves 121 airports in 12 countries with a point-to-point domestic model. Primary markets include MDW, DAL, LAS, DEN, BWI, HOU, MCO, and PHX. Southwest flies to Hawaii, Mexico, Central America, and the Caribbean. No widebody aircraft, no alliance partnerships.

Frontier serves approximately 120 destinations with a hub-light model centered on Denver (DEN), with significant operations from Orlando (MCO), Las Vegas (LAS), Atlanta (ATL), Philadelphia (PHL), and Miami (MIA). Frontier’s network focuses on major domestic markets. International service is limited to Mexico and the Caribbean.

On routes where both compete (Denver to Las Vegas, Orlando to Chicago, Phoenix to Dallas), fares are competitive and the comparison comes down to bags and reliability. Southwest typically runs more daily frequencies on these shared routes.

Winner: domestic breadth

Tie / Southwest 121 airports vs Frontier ~120 destinations

Winner: flight frequency

Southwest / more daily departures on popular routes

Winner: Hawaii

Southwest / Frontier does not serve Hawaii

Winner: international leisure

Southwest / more Mexico, Central America, Caribbean routes

Is the Companion Pass or GoWild Pass a better deal?

The Companion Pass is better for planned travel with a partner. GoWild is better for solo, spontaneous travelers who can book one day in advance.

Both airlines have a signature loyalty feature, but they work completely differently.

Southwest Rapid Rewards earns points based on fare price with no blackout dates. Free flight changes and cancellations on most fares. The Companion Pass (135,000 qualifying points or 100 flights in a calendar year) lets a designated companion fly free on every flight for the rest of that year and the entire following year. For couples and families who fly Southwest regularly, the Companion Pass can save thousands of dollars annually.

Frontier FRONTIER Miles earns miles on flights and purchases. The loyalty program is less developed than Rapid Rewards but has one unique feature: the GoWild All-You-Can-Fly Pass at $349 to $599 per year. GoWild lets you book unlimited flights for one cent plus taxes and fees (typically $14 to $40 per flight). The catch: domestic flights can only be booked one day in advance. You must be extremely flexible, live near a Frontier hub, and travel with only a personal item to make it work.

The Companion Pass is the better value for planned travel. You know your flights in advance, you book a companion free, and you save money predictably. GoWild is the better value for spontaneous, flexible travelers who can fly on 24 hours’ notice and do not need a bag. These are very different travel styles.

Winner: planned travel savings

Rapid Rewards / Companion Pass

Winner: spontaneous/flexible travel

FRONTIER Miles / GoWild Pass at $349-599/year

Winner: flexibility

Rapid Rewards / free changes, no blackout dates

Winner: point value

Rapid Rewards / Varies; Rapid Rewards usually wins on flexibility

Is a Southwest fare or a Frontier bundle cheaper overall?

Southwest’s all-in fare is usually cheaper than a Frontier Basic fare once you add a carry-on and seat, because those per-direction add-ons close the fare gap quickly.

Since Frontier strips everything from the Basic fare, comparing Frontier’s bundles to Southwest’s all-in fares is the most honest way to evaluate total cost.

Frontier’s New Frontier bundles roll the extras into the fare instead of charging à la carte. Economy adds the carry-on, a standard seat, and no change or cancel fees. Premium adds a premium extra-legroom seat plus Board First for guaranteed overhead bin space. Business adds two checked bags (50 lb, or 23 kg, each) and an UpFront Plus seat (empty middle or 2x2). Frontier prices these bundles dynamically by route and date rather than at a fixed dollar amount, and each one costs more than the Basic fare it builds on.

Southwest’s Basic fare (the entry-level fare formerly called Wanna Get Away) includes a carry-on and personal item. Checked bag is $45. A seat is assigned at check-in on Basic, and you can select a seat at booking on the higher Choice, Choice Preferred, and Choice Extra fares. Changes are free (fare difference or credit applies).

On many routes, a Southwest Basic fare is cheaper than a Frontier Basic fare plus the Economy bundle (or the standalone carry-on and a seat), because those add-ons close the fare gap quickly. The only scenario where Frontier is consistently cheaper with a bundle is on routes where Frontier’s base fare is $50 or more below Southwest’s. That happens on some routes but not most.

Winner: bundled value

Southwest / most inclusions at the base fare level

Winner: base fare transparency

Frontier / you see exactly what you pay for

Who Should Pick Southwest

• You travel with a carry-on and want it included in the fare
• You value on-time reliability (77.04 percent on-time, versus Frontier ranking last of 10, per US DOT full-year 2025)
• You fly with a partner or family and can earn the Companion Pass
• You want free changes and cancellations without penalty
• You need higher daily flight frequency for rebooking flexibility
• You fly to Hawaii (Frontier does not serve Hawaii)
• You carry a bag over 35 pounds (16 kg), Frontier’s enforced carry-on cap, since Southwest publishes no carry-on weight limit

Who Should Pick Frontier

• You always fly personal-item-only and never check or carry on a bag
• You want the absolute lowest base fare and are willing to skip every extra
• You have a flexible schedule and the GoWild Pass makes sense for your lifestyle
• You want an UpFront Plus seat with a guaranteed empty middle seat next to you
• You fly routes where Frontier’s base fare is significantly lower than Southwest’s
• You do not mind the risk of a higher cancellation rate and lower on-time performance

The Bottom Line

Southwest and Frontier represent the two poles of domestic US air travel pricing. Southwest bundles everything into the fare and charges a higher base price. Frontier strips everything out and charges a lower base price. The question is not which airline is cheaper in the abstract. The question is which is cheaper for you, on your route, with your bags.

For the personal-item-only traveler who packs light and values the lowest possible total cost, Frontier wins. The base fares are lower, and you pay nothing extra. For everyone else, add Frontier’s carry-on fee for your route to the base fare and compare it to Southwest’s all-in price. More often than not, Southwest is the same price or less, and you get a free carry-on, higher reliability, Companion Pass eligibility, and free changes.

The reliability gap seals it for risk-averse travelers. Southwest’s 0.85 percent cancellation rate is less than half of Frontier’s 1.77 percent, and Southwest posts a strong 77.04 percent on-time arrival rate while Frontier finished last of 10 on on-time arrivals (US DOT full-year 2025). If getting there on time is worth paying a modest premium, Southwest is the clear pick. If Frontier’s lower fare is worth accepting more delays, Frontier has earned its market.

For more comparisons, see JetBlue vs Frontier and Southwest vs Spirit (kept for reference now that Spirit has shut down).