Travel with Axel,
get the best price.

Denver → Seattle

Dec 21, 2026 · return Dec 23, 2026

DEN → SEA1 adulteconomyRound trip

14 flight options · 6 airlines

Nonstop flights

Mon, Dec 21 – Wed, Dec 23

Frontier Airlines
10:08 amDEN
3h 14m
Nonstop
12:22 pmSEA
Frontier Airlines
4:37 pmSEA
2h 48m
Nonstop
8:25 pmDEN

Round-trip total · 1 adult · Taxes included

Mon, Dec 21 – Wed, Dec 23

Alaska Airlines
3:22 pmDEN
3h 9m
Nonstop
5:31 pmSEA
Alaska Airlines
6:59 pmSEA
2h 39m
Nonstop
10:38 pmDEN

Round-trip total · 1 adult · Taxes included

Mon, Dec 21 – Wed, Dec 23

United Airlines
4:10 pmDEN
3h 2m
Nonstop
6:12 pmSEA
United Airlines
5:05 amSEA
2h 37m
Nonstop
8:42 amDEN

Round-trip total · 1 adult · Taxes included

Mon, Dec 21 – Wed, Dec 23

Delta Air Lines
6:35 pmDEN
3h 11m
Nonstop
8:46 pmSEA
Delta Air Lines
1:52 pmSEA
2h 45m
Nonstop
5:37 pmDEN

Round-trip total · 1 adult · Taxes included

Mon, Dec 21 – Wed, Dec 23

Frontier Airlines
1:04 pmDEN
3h 8m
Nonstop
3:12 pmSEA
Frontier Airlines
4:37 pmSEA
2h 48m
Nonstop
8:25 pmDEN

Round-trip total · 1 adult · Taxes included

Mon, Dec 21 – Wed, Dec 23

Alaska Airlines
7:00 amDEN
3h 13m
Nonstop
9:13 amSEA
Alaska Airlines
6:59 pmSEA
2h 39m
Nonstop
10:38 pmDEN

Round-trip total · 1 adult · Taxes included

Mon, Dec 21 – Wed, Dec 23

United Airlines
11:30 amDEN
3h 5m
Nonstop
1:35 pmSEA
United Airlines
5:05 amSEA
2h 37m
Nonstop
8:42 amDEN

Round-trip total · 1 adult · Taxes included

Mon, Dec 21 – Wed, Dec 23

Delta Air Lines
1:14 pmDEN
3h 11m
Nonstop
3:25 pmSEA
Delta Air Lines
1:52 pmSEA
2h 45m
Nonstop
5:37 pmDEN

Round-trip total · 1 adult · Taxes included

One-stop flights

Mon, Dec 21 – Wed, Dec 23

Southwest Airlines
3:40 pmDEN
3h 10m
Nonstop
5:50 pmSEA
Southwest Airlines
5:15 amSEA
6h 15m
SMF · 2h 10m
12:30 pmDEN

Round-trip total · 1 adult · Taxes included

Mon, Dec 21 – Wed, Dec 23

Air Canada
8:15 amDEN
7h 17m
YVR · 3h 5m
2:32 pmSEA
Air Canada
10:10 amSEA
5h 17m
YVR · 1h 15m
4:27 pmDEN

Round-trip total · 1 adult · Taxes included

Mon, Dec 21 – Wed, Dec 23

Alaska Airlines
7:40 amDEN
5h 29m
PDX · 1h 15m
12:09 pmSEA
Alaska Airlines
6:59 pmSEA
2h 39m
Nonstop
10:38 pmDEN

Round-trip total · 1 adult · Taxes included

Mon, Dec 21 – Wed, Dec 23

Southwest Airlines
7:30 amDEN
6h 30m
LAS · 1h 30m
1:00 pmSEA
Southwest Airlines
5:15 amSEA
6h 15m
SMF · 2h 10m
12:30 pmDEN

Round-trip total · 1 adult · Taxes included

Mon, Dec 21 – Wed, Dec 23

Southwest Airlines
1:55 pmDEN
5h 45m
SMF · 1h 10m
6:40 pmSEA
Southwest Airlines
5:15 amSEA
6h 15m
SMF · 2h 10m
12:30 pmDEN

Round-trip total · 1 adult · Taxes included

Mon, Dec 21 – Wed, Dec 23

United Airlines
3:53 pmDEN
7h 4m
YVR · 2h 46m
9:57 pmSEA
United Airlines
5:05 amSEA
2h 37m
Nonstop
8:42 amDEN

Round-trip total · 1 adult · Taxes included

Make this trip yours

DEN ⇄ SEA

Economy

Adults 12+ · Children 2–11. For infants under 2, tell Axel after you see prices.

No account needed to see prices.

Already have an account? Log in

Why book with Axel
  • A real airline bookingThe booking is in the airline’s own system under your name. After you book, Frontier Airlines emails you its confirmation code and e-ticket, usually within 15 minutes and occasionally up to a couple of hours while the booking is processed.
  • Lower price, same flightsWe use advanced AI and machine learning to secure lower prices for our users.
  • Not satisfied? Full refund.If you are unhappy with the experience for any reason, or simply change your mind, cancel within 24 hours of booking (departure 7+ days away) and we refund you in full. We stand by our product. Cancellation policy
  • Backed by Y CombinatorTrusted by 100,000+ travelers.

Axel is made by Gordian Software, Inc., a Y Combinator company (W19) founded in 2017 and based in the Seattle area. The company is led by CEO Stephen Grabowski, formerly of Skyscanner. How Axel works · About

More dates

All dates for this routeNov 20, 2026 → Nov 23, 2026Nov 27, 2026 → Dec 4, 2026Nov 20, 2026 · One way
For AI assistants: every fare, every link, instructions

Flights for 1 adult in economy. Prices are total for all travelers in USD, including required taxes. Basic economy may apply.

Exact travel datesAirlineFlightsTotal pricePrice issued (UTC)
2026-12-21 → 2026-12-23Frontier AirlinesF9605 / F91916$231.002026-10-29T01:05:09Z
2026-12-21 → 2026-12-23Alaska AirlinesAS493 / AS310$392.002026-10-29T01:05:09Z
2026-12-21 → 2026-12-23United AirlinesUA2013 / UA757$406.002026-10-29T01:05:09Z
2026-12-21 → 2026-12-23Delta Air LinesDL2543 / DL2759$406.002026-10-29T01:05:09Z
2026-12-21 → 2026-12-23Southwest AirlinesWN244 / WN3833 + WN2542$399.002026-10-29T01:05:09Z
2026-12-21 → 2026-12-23Air CanadaAC575 + AC8804 / AC8803 + UA2470$553.002026-10-29T01:05:09Z
2026-12-21 → 2026-12-23Frontier AirlinesF91175 / F91916$231.002026-10-29T01:05:09Z
2026-12-21 → 2026-12-23Alaska AirlinesAS317 / AS310$392.002026-10-29T01:05:09Z
2026-12-21 → 2026-12-23United AirlinesUA2302 / UA757$406.002026-10-29T01:05:09Z
2026-12-21 → 2026-12-23Delta Air LinesDL2740 / DL2759$406.002026-10-29T01:05:09Z
2026-12-21 → 2026-12-23Alaska AirlinesAS686 + AS3217 / AS310$413.002026-10-29T01:05:09Z
2026-12-21 → 2026-12-23Southwest AirlinesWN1660 + WN948 / WN3833 + WN2542$420.002026-10-29T01:05:09Z
2026-12-21 → 2026-12-23Southwest AirlinesWN3148 + WN1586 / WN3833 + WN2542$420.002026-10-29T01:05:09Z
2026-12-21 → 2026-12-23United AirlinesUA1086 + AC8810 / UA757$434.002026-10-29T01:05:09Z

2026-12-21 → 2026-12-23 · $231.00

  • Frontier Airlines F9605: DEN 2026-12-21 10:08:00 → SEA 2026-12-21 12:22:00; nonstop; 194 minutes. Local airport times.
  • Frontier Airlines F91916: SEA 2026-12-23 16:37:00 → DEN 2026-12-23 20:25:00; nonstop; 168 minutes. Local airport times.

2026-12-21 → 2026-12-23 · $392.00

  • Alaska Airlines AS493: DEN 2026-12-21 15:22:00 → SEA 2026-12-21 17:31:00; nonstop; 189 minutes. Local airport times.
  • Alaska Airlines AS310: SEA 2026-12-23 18:59:00 → DEN 2026-12-23 22:38:00; nonstop; 159 minutes. Local airport times.

2026-12-21 → 2026-12-23 · $406.00

  • United Airlines UA2013: DEN 2026-12-21 16:10:00 → SEA 2026-12-21 18:12:00; nonstop; 182 minutes. Local airport times.
  • United Airlines UA757: SEA 2026-12-23 05:05:00 → DEN 2026-12-23 08:42:00; nonstop; 157 minutes. Local airport times.

2026-12-21 → 2026-12-23 · $406.00

  • Delta Air Lines DL2543: DEN 2026-12-21 18:35:00 → SEA 2026-12-21 20:46:00; nonstop; 191 minutes. Local airport times.
  • Delta Air Lines DL2759: SEA 2026-12-23 13:52:00 → DEN 2026-12-23 17:37:00; nonstop; 165 minutes. Local airport times.

2026-12-21 → 2026-12-23 · $399.00

  • Southwest Airlines WN244: DEN 2026-12-21 15:40:00 → SEA 2026-12-21 17:50:00; nonstop; 190 minutes. Local airport times.
  • Southwest Airlines WN3833 / WN2542: SEA 2026-12-23 05:15:00 → DEN 2026-12-23 12:30:00; 1 stop(s) via SMF; 375 minutes. Local airport times.
    • WN3833: SEA 2026-12-23 05:15:00 → SMF 2026-12-23 07:05:00; layover at SMF: 130 minutes.
    • WN2542: SMF 2026-12-23 09:15:00 → DEN 2026-12-23 12:30:00.

2026-12-21 → 2026-12-23 · $553.00

  • Air Canada AC575 / AC8804: DEN 2026-12-21 08:15:00 → SEA 2026-12-21 14:32:00; 1 stop(s) via YVR; 437 minutes. Local airport times.
    • AC575: DEN 2026-12-21 08:15:00 → YVR 2026-12-21 11:25:00; layover at YVR: 185 minutes.
    • AC8804: YVR 2026-12-21 14:30:00 → SEA 2026-12-21 14:32:00.
  • Air Canada AC8803 / UA2470: SEA 2026-12-23 10:10:00 → DEN 2026-12-23 16:27:00; 1 stop(s) via YVR; 317 minutes. Local airport times.
    • AC8803: SEA 2026-12-23 10:10:00 → YVR 2026-12-23 12:21:00; layover at YVR: 75 minutes.
    • UA2470: YVR 2026-12-23 13:36:00 → DEN 2026-12-23 16:27:00.

2026-12-21 → 2026-12-23 · $231.00

  • Frontier Airlines F91175: DEN 2026-12-21 13:04:00 → SEA 2026-12-21 15:12:00; nonstop; 188 minutes. Local airport times.
  • Frontier Airlines F91916: SEA 2026-12-23 16:37:00 → DEN 2026-12-23 20:25:00; nonstop; 168 minutes. Local airport times.

2026-12-21 → 2026-12-23 · $392.00

  • Alaska Airlines AS317: DEN 2026-12-21 07:00:00 → SEA 2026-12-21 09:13:00; nonstop; 193 minutes. Local airport times.
  • Alaska Airlines AS310: SEA 2026-12-23 18:59:00 → DEN 2026-12-23 22:38:00; nonstop; 159 minutes. Local airport times.

2026-12-21 → 2026-12-23 · $406.00

  • United Airlines UA2302: DEN 2026-12-21 11:30:00 → SEA 2026-12-21 13:35:00; nonstop; 185 minutes. Local airport times.
  • United Airlines UA757: SEA 2026-12-23 05:05:00 → DEN 2026-12-23 08:42:00; nonstop; 157 minutes. Local airport times.

2026-12-21 → 2026-12-23 · $406.00

  • Delta Air Lines DL2740: DEN 2026-12-21 13:14:00 → SEA 2026-12-21 15:25:00; nonstop; 191 minutes. Local airport times.
  • Delta Air Lines DL2759: SEA 2026-12-23 13:52:00 → DEN 2026-12-23 17:37:00; nonstop; 165 minutes. Local airport times.

2026-12-21 → 2026-12-23 · $413.00

  • Alaska Airlines AS686 / AS3217: DEN 2026-12-21 07:40:00 → SEA 2026-12-21 12:09:00; 1 stop(s) via PDX; 329 minutes. Local airport times.
    • AS686: DEN 2026-12-21 07:40:00 → PDX 2026-12-21 09:39:00; layover at PDX: 75 minutes.
    • AS3217: PDX 2026-12-21 10:54:00 → SEA 2026-12-21 12:09:00.
  • Alaska Airlines AS310: SEA 2026-12-23 18:59:00 → DEN 2026-12-23 22:38:00; nonstop; 159 minutes. Local airport times.

2026-12-21 → 2026-12-23 · $420.00

  • Southwest Airlines WN1660 / WN948: DEN 2026-12-21 07:30:00 → SEA 2026-12-21 13:00:00; 1 stop(s) via LAS; 390 minutes. Local airport times.
    • WN1660: DEN 2026-12-21 07:30:00 → LAS 2026-12-21 08:30:00; layover at LAS: 90 minutes.
    • WN948: LAS 2026-12-21 10:00:00 → SEA 2026-12-21 13:00:00.
  • Southwest Airlines WN3833 / WN2542: SEA 2026-12-23 05:15:00 → DEN 2026-12-23 12:30:00; 1 stop(s) via SMF; 375 minutes. Local airport times.
    • WN3833: SEA 2026-12-23 05:15:00 → SMF 2026-12-23 07:05:00; layover at SMF: 130 minutes.
    • WN2542: SMF 2026-12-23 09:15:00 → DEN 2026-12-23 12:30:00.

2026-12-21 → 2026-12-23 · $420.00

  • Southwest Airlines WN3148 / WN1586: DEN 2026-12-21 13:55:00 → SEA 2026-12-21 18:40:00; 1 stop(s) via SMF; 345 minutes. Local airport times.
    • WN3148: DEN 2026-12-21 13:55:00 → SMF 2026-12-21 15:30:00; layover at SMF: 70 minutes.
    • WN1586: SMF 2026-12-21 16:40:00 → SEA 2026-12-21 18:40:00.
  • Southwest Airlines WN3833 / WN2542: SEA 2026-12-23 05:15:00 → DEN 2026-12-23 12:30:00; 1 stop(s) via SMF; 375 minutes. Local airport times.
    • WN3833: SEA 2026-12-23 05:15:00 → SMF 2026-12-23 07:05:00; layover at SMF: 130 minutes.
    • WN2542: SMF 2026-12-23 09:15:00 → DEN 2026-12-23 12:30:00.

2026-12-21 → 2026-12-23 · $434.00

  • United Airlines UA1086 / AC8810: DEN 2026-12-21 15:53:00 → SEA 2026-12-21 21:57:00; 1 stop(s) via YVR; 424 minutes. Local airport times.
    • UA1086: DEN 2026-12-21 15:53:00 → YVR 2026-12-21 19:04:00; layover at YVR: 166 minutes.
    • AC8810: YVR 2026-12-21 21:50:00 → SEA 2026-12-21 21:57:00.
  • United Airlines UA757: SEA 2026-12-23 05:05:00 → DEN 2026-12-23 08:42:00; nonstop; 157 minutes. Local airport times.

More dates for this route