Frontier vs Southwest 2026: All-In Fee Comparison After May 2025

Frontier's headline fare almost always looks cheaper than Southwest's, so it seems like the obvious budget pick. But ultra-low-cost carriers make their money on the add-ons, bags, seats, changes, that don't show up until checkout. The real question is which airline costs less once your actual trip is fully loaded.

The verdict

For travellers packing only a personal item (under-seat bag) with no seat preference, Frontier is slightly cheaper than Southwest, by $10, $30 on average. For everyone else, anyone needing a carry-on, wanting to pick a seat, or valuing the ability to cancel, Southwest's higher base fare results in equal or lower total cost after fees. This holds for most domestic routes where both carriers compete. The exceptions are Frontier's GoWild! All-You-Can-Fly pass ($599/year regular price) (Frontier) for ultra-frequent budget travellers, and specific routes where Frontier drops base fares below $29 as loss leaders, genuine deals that beat any Southwest equivalent.

💡 Compare budget flights on ShopBack, earn cashback on Southwest and other carriers to reduce your all-in cost Takes 2 minutes to sign up. No promo codes needed.

---

What's changed in 2026

The biggest recent shift on this comparison is on the Southwest side, not the Frontier side.

Southwest ended its Bags Fly Free policy on 28 May 2025. Southwest announced the change on 11 March 2025 (The New York Times). As of July 2026, most Southwest fares now carry a $35 first checked bag fee and a $45 second checked bag fee (CBS News). This is Southwest's first-ever routine checked bag fee since the airline's founding. Free checked bags are retained for A-List Preferred Rapid Rewards members, Business Select fare buyers, and holders of eligible Southwest Rapid Rewards credit cards (Priority, Premier, Plus). Carry-on bags and one personal item still fly free on all Southwest fares.

What that means for the Frontier comparison. Southwest's historical differentiator ("two free checked bags") is gone for the general-fare traveller, but the carry-on differentiator (which is the more common bag choice) remains intact. Frontier still charges $45 to $99 for a carry-on bag, and Southwest is still $0. On checked bags, Southwest is now $35 versus Frontier's $45 to $99, so Southwest is still cheaper on checked bags for most fare classes, just by less than before.

Southwest also transitioned to assigned seating in 2025. Alongside the baggage change, Southwest ended its open-seating boarding model in favour of standard assigned seats on 28 May 2025 (Wikipedia). Basic seat selection remains complimentary on booked fares, though specific seats (extra-legroom, up-front rows) can carry an added fee similar to major legacy carriers.

Frontier's baggage and seat-fee bands and its GoWild! All-You-Can-Fly annual pass are structurally unchanged. Frontier World Mastercard bundled benefits (waived carry-on, waived first checked bag, waived seat selection) also carry forward as a way to blunt Frontier's fee stack for regular Frontier flyers.

---

How the two pricing models differ

Frontier operates a pure unbundled model, you pay for every component separately. The base fare covers a seat and a personal item only. A carry-on bag costs $45, $99 (depending on when you add it), a checked bag costs $45, $99, and a seat assignment costs $15, $50. For a traveller who adds just a carry-on, the total jumps by $45, $99 each way.

Southwest's model still includes carry-on bags and one personal item at no extra cost, on all fares. Southwest's advantage narrowed after two 2025 policy changes: the $35 first checked bag fee that took effect 28 May 2025 (CBS News), and the transition from open seating to assigned seating on the same date. Carry-on bags remain free on Southwest, which is the key differentiator for most travellers.

---

The fees, side by side

Fee Category	Frontier (typical)	Southwest (typical)
Base fare (example route)	$49	$89
Personal item (under seat)	Free	Free
Carry-on bag (overhead)	$45, $99	Free
1st checked bag	$45, $99	$35 (free with SW card)
Seat assignment	$15, $50	Free (open seating)
Flight change fee	$99	$0 credit retained
Total (personal item only)	$49	$89
Total (carry-on + seat)	$109, $198	$89
Total (carry-on + checked + seat)	$154, $297	$124

The numbers show that Frontier's cost advantage disappears the moment you add a carry-on bag, at that point, Southwest's higher base fare results in equal or lower all-in spending.

Search US budget-flight OTA searches and earn cashback: Skyscanner · Trip.com

---

Run the fee-stack test

Use the Frontier Fee Stack Test: start with Frontier's base fare and add the fees for every service you'll actually use. If the total exceeds Southwest's base fare for the same route, book Southwest. If Frontier's all-in cost is still lower, book Frontier.

The test rarely favours Frontier for travellers with bags. It consistently favours Frontier for true minimalists (personal item only, no seat preference, no risk of itinerary change).

Traveller Type	Best Choice	Reason
Personal item only, flexible, low change risk	Frontier	Saves $30, $50 vs Southwest base fare
Carry-on bag + seat preference	Southwest	Frontier adds $60, $150 in fees
Family of 4, checked bags	Southwest	SW carry-on free; Frontier adds $360, $800 in bag fees
Traveller with uncertain itinerary	Southwest	Frontier's $99 change fee erases any fare saving
Frequent budget flyer (20+ trips/year)	Frontier GoWild pass	$599/year all-you-can-fly is unbeatable at volume

---

What it means for your booking

Booking Southwest through ShopBack earns cashback on the base fare, on a $158 all-in Southwest round-trip, that's $8, $16 back, further widening the advantage over Frontier's $208 all-in cost after carry-on fees.

In practice, this means most travellers should book Southwest unless they are genuinely travelling with a personal item only and have a fixed itinerary with no possibility of change. The typical American traveller brings at least a carry-on bag, and that single add-on is enough to make Southwest cheaper.

A concrete example: two friends flying from Denver to Las Vegas. Frontier base fare: $39. Southwest base fare: $79. Frontier advantage: $40. Both travellers have a carry-on. Frontier overhead carry-on: $65 each way x 2 = $130 round-trip. Southwest carry-on: free. All-in: Frontier $208 vs Southwest $158. Southwest is $50 cheaper, despite the lower Frontier base fare.

Book hotels for the destination end of your budget flight with cashback: Booking.com · Agoda · Hotels.com · Marriott

---

Worked example: three US traveller profiles in August 2026

Fare bands here are representative of typical August 2026 pricing on the routes named. Verify current fares on the airline sites or via a comparison tool like Skyscanner before booking. All-in totals include base fare plus fees as noted.

Traveller A: solo weekend trip, DEN to LAS, personal item only, no seat preference, fixed dates. Frontier base fare $39 round-trip during a routine off-peak sale. Personal item fits under seat, no carry-on fee. No seat assignment. All-in Frontier: $39. Southwest same-day fare DEN to LAS: $89 round-trip. Personal item free. Carry-on free (which the traveller does not need on this trip). All-in Southwest: $89. Verdict: Frontier saves $50 on this specific personal-item-only itinerary. This is the narrow lane where Frontier wins.

Traveller B: solo work trip, DEN to LAX, laptop bag plus one carry-on suitcase, aisle-seat preference, plans might slip a day. Frontier base fare $69 round-trip. Carry-on overhead $65 each way = $130. Aisle-seat assignment $19 each way = $38. Potential change fee $99. All-in Frontier (excluding potential change): $237. All-in Frontier if change is needed: $336. Southwest same-day fare DEN to LAX: $128 round-trip. Personal item free, carry-on free, seat assignment free after the May 2025 assigned-seating transition (basic seat), no change fee (travel credit retained on cancellation). All-in Southwest: $128. Verdict: Southwest saves $109 to $208 depending on whether a change is needed. This is the typical business traveller profile and Southwest wins clearly.

Traveller C: family of four, MDW to Orlando, spring-break trip, two checked bags, want to sit together. Frontier base fare $59 per person round-trip: $236 for four. Carry-on $65 each way each person = $520. Two checked bags $65 each way each = $260. Seat assignment together $25 per person each way = $200. All-in Frontier: $1,216. Southwest same-week fare MDW to MCO: $198 per person round-trip = $792. Personal items free, carry-ons free. Two checked bags at $35 first bag + $45 second bag each way = $640 for four people two-way, or $0 if the family holds a Southwest Rapid Rewards credit card that includes a free first checked bag. Assigned seats free at basic level. All-in Southwest without card: $1,432. All-in Southwest with credit card free bags: $952. Verdict: Frontier saves the family $216 to $216 relative to Southwest without the card, but loses by $216 relative to Southwest with the card. Even in the fee-heavy family case, the gap is now much closer to a coin-toss than it used to be, which is a direct consequence of Southwest's May 2025 policy change.

The pattern: Frontier's win is narrow and depends on truly minimal baggage plus fixed itinerary. Southwest's win is wide any time a carry-on, an itinerary-change risk, or a Southwest credit card enters the picture. The May 2025 baggage change narrowed but did not close Southwest's structural advantage for the median US traveller.

---

When this does NOT apply

• Frontier's sub-$29 loss-leader sales: Frontier periodically runs route-specific sales at $19, $29 base fares. At this price, even adding a carry-on fee keeps the total below Southwest's fare. Monitor Frontier's email list or deal sites for these.
• Frontier GoWild All-You-Can-Fly Pass ($599/year): For travellers flying 20+ times annually with flexibility on timing, this pass makes Frontier the clear winner, no other US airline offers an all-inclusive unlimited flying model.
• Routes without Southwest service: Frontier operates some routes that Southwest doesn't (smaller markets, some Florida routes). On those, Frontier is the only budget option.
• Travellers with the Frontier credit card: The Frontier World Mastercard ($89/year) includes free carry-on bag + first checked bag + seat selection, eliminating the main fee disadvantages and making Frontier competitive even for bag-carrying travellers.
• One-way trips with minimal luggage: The Frontier base fare advantage is most pronounced on one-way bookings where the fee asymmetry doesn't compound over a round-trip.

Book chain hotels and vacation rentals near budget-airline hubs with cashback: IHG · VRBO

Compare flight-and-hotel packages and airport-transfer activities with cashback: Expedia · Klook

---

Frequently asked questions

Does Southwest still fly bags free in 2026?

No. Southwest ended its long-standing Bags Fly Free policy on 28 May 2025 (The New York Times). As of July 2026, most Southwest fares carry a $35 first checked bag fee and a $45 second checked bag fee (CBS News). Carry-on bags and one personal item remain free. Free checked bags are retained for A-List Preferred Rapid Rewards members, Business Select fare buyers, and holders of eligible Southwest Rapid Rewards Priority, Premier, and Plus credit cards.

How does the Southwest 2025 baggage change affect the Frontier comparison?

Southwest's historical bags-fly-free advantage narrowed but did not disappear. Carry-on bags remain free on Southwest, which is the more common bag choice for domestic travellers, versus Frontier's $45 to $99 carry-on fee. On checked bags Southwest is now $35 versus Frontier's $45 to $99, so Southwest is still cheaper for most fare classes, just by less than before. Southwest's carry-on and seat-selection advantages continue to be the two largest drivers of its all-in win over Frontier. Southwest Rapid Rewards credit cardholders retain a free first checked bag on eligible cards, which restores the pre-2025 advantage for cardholders.

Is Spirit or Frontier cheaper than Southwest?

Both Spirit and Frontier have lower base fares, but their fee structures are nearly identical, carry-on bags, seat assignments, and change fees add up quickly. For most travellers with any luggage, Southwest's all-in pricing is competitive or cheaper.

Does Frontier have better routes than Southwest?

Frontier has a somewhat different route network, stronger in Denver hub routes and some secondary markets. Southwest dominates in Texas, the Southwest, and point-to-point leisure routes. Neither is strictly "better", coverage depends on your origin city.

How can I earn cashback on budget flights and hotels in the US?

Direct Frontier and Southwest airline bookings usually do not earn cashback. Route your flight comparison through Skyscanner or Trip.com if you plan to book on an OTA that ShopBack tracks. For paired hotels use Booking.com, Agoda, Hotels.com, or Marriott. Cashback rates vary by merchant and change monthly; verify the current published rate on each merchant page before booking.

Does ShopBack work for VRBO and Klook bookings on a budget-airline trip?

Yes. Both VRBO and Klook are ShopBack US partners. VRBO covers whole-home vacation rentals across US leisure markets (Vegas, Orlando, Florida beaches, ski towns). Klook covers airport transfers, attraction tickets, and activities on the destination end. Activate ShopBack before clicking through and complete the booking in one session; cashback tracks on eligible order value.

Which booking site is cheapest for budget-flight hotels, Booking.com, Agoda, Hotels.com or Marriott?

No single site is consistently cheapest. Booking.com has the largest inventory with flexible cancellation, Agoda prices aggressively on Asia and Latin America stays, Hotels.com rewards repeat bookings through One Key, and Marriott direct often matches OTAs on Bonvoy properties. Prices on the same room can differ 5 to 15 percent; compare all four before locking in, then route through ShopBack for cashback on top.

Can I get cashback on a flight and hotel package instead of a Frontier or Southwest ticket?

Yes. Packages are a distinct listing on Expedia and Trip.com, where the combined price sometimes beats booking a budget carrier plus a separate hotel once fees are added. Activate ShopBack before clicking through; cashback tracks on eligible package spend at the current published rate on each merchant page. Compare the bundle price against a full fee-stacked Frontier or Southwest total before deciding.

How much cashback can I earn on a US budget-airline trip through ShopBack?

Cashback depends on which merchants you use and their current published rate; ShopBack does not guarantee a flat rate across travel. On a typical budget-airline trip, cashback lands on the non-airline pieces: hotels on Booking.com, Agoda, or Marriott, a chain stay on IHG, activities on Klook, and any OTA-booked flight leg via Skyscanner or Trip.com. Check the live rate on each merchant page before booking.

Where can I book a hotel for a budget-airline trip with cashback?

For chain hotels near budget-airline hubs (Denver, Las Vegas, Nashville, Orlando, Baltimore, Chicago Midway), the main ShopBack partners are Marriott (Bonvoy portfolio) and IHG (Holiday Inn, Kimpton, InterContinental family). For OTAs, Booking.com, Agoda, and Hotels.com all track through ShopBack. Activate ShopBack, click through, and complete the booking in one session.

Should I book my Frontier or Southwest ticket via an OTA to earn cashback?

Only if the OTA fare matches airline direct and the OTA is a ShopBack US partner. Neither Frontier nor Southwest sells widely through third-party OTAs (Southwest is famously airline-direct only, and Frontier caps OTA inventory), so most flight cashback opportunities are through Skyscanner or Trip.com redirecting to a competing OTA carrier. If the itinerary must be Frontier or Southwest, book direct and route the hotel or activity spend through ShopBack instead.

---

Key takeaways

• If you're packing a personal item only and have a fixed itinerary, Frontier can save $30, $50 over Southwest
• If you need a carry-on bag, Southwest is equal or cheaper than Frontier all-in
• If your itinerary might change, Southwest's retained travel credit beats Frontier's $99 change fee every time
• If you fly 20+ times a year and can be flexible, look at Frontier's GoWild pass, nothing else competes at that volume
• If you have the Frontier credit card, the fee advantage narrows significantly and Frontier becomes more competitive
• Book Southwest through ShopBack, $8, $16 cashback on a $158 all-in fare further widens the gap over Frontier's fee-laden total, no promo codes needed

💡 Book budget flights on ShopBack, cashback on every booking, no promo codes needed Takes 2 minutes to sign up. No promo codes needed.

---

Related articles

• Best Time to Book Domestic Flights for the Cheapest Fares: What Data Shows (2026)
• Airbnb vs Hotel in Las Vegas: Which Actually Saves You More in 2026?
• Best US Airline Credit Cards in 2026: Delta, United, American, Alaska, Southwest Compared
• Carry-On Only vs Checked Bags: Real Cost Difference Across US Airlines (2026)

Sources

• Frontier Airlines, GoWild! All-You-Can-Fly Pass (unlimited flights, bags and seats sold separately; $599 regular annual price)
• CBS News, Southwest's first checked bag fee ($35 first bag, $45 second; carry-on remains free), effective May 2025

Note: Specific base fares, carry-on and seat-selection fees, and all-in totals in this article are illustrative examples based on typical 2026 pricing; fees vary dynamically by route, date, and booking channel. Verify current fees with each airline before booking.

---

Disclaimer

The views and recommendations expressed in this article are those of the author.

Prices, rates, promotions, and availability are subject to change. Please verify details directly with the relevant providers before making any decisions.

This article is intended for general informational purposes only and should not be considered professional, financial, or travel advice.

---

Brands, work with us: garry@shopback.com.