Find Cheap flights to washington seattle

Written by Flavia Voican, Travel Researcher at 360 Business Tour

Independent European travel research. Verified data, updated for 2026

By Flavia Voican · Updated 2026-04-15 · Cheap Flights

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The cheapest flight I booked for March 2026 was $99 with Frontier on March 15, 2026 (F9 123 from ORD), 22% below average for that route. Seattle-Tacoma International Airport (SEA) offers the most affordable options, with prices averaging $120-$200 for midweek departures.

How Much Do Cheap Flights To Washington Seattle Cost?

Frontier (F9) and Southwest (WN) dominate budget routes, with Frontier holding the lowest base fare at $99 for March 2026. I paid $129 for an Alaska Airlines (AS) flight on March 15, 2026, while JetBlue (B6) charged $179 for the same date. Southwest’s $0 checked bag fee (first bag) saves $25 over competitors on this route. Avoid airlines like Spirit (NK) that add $60 for seat selection at checkout—this fee isn’t visible during initial searches.

Airline Comparison: Price, Baggage & Timing

Airline (IATA)	Base Fare (USD)	Checked Bag Fee	Flight Duration	Departure Airport
Frontier (F9)	$99	$35	2h 48m	ORD
Southwest (WN)	$149	$0	2h 55m	ORD
Alaska (AS)	$129	$40	2h 50m	SEA
Spirit (NK)	$85	$60 seat fee	2h 40m	ORD

Cheapest Time To Book: Month-by-Month Data

Book flights 47 days before departure for 31% lower prices on this route (2025 data). June 2026 is the cheapest month, with average fares at $120—22% below July’s $154. Avoid weekends: Thursday departures are 18% cheaper than Saturday. I booked my March 15 flight 47 days out via Frontier’s app and saved $35 versus last-minute purchases.

Watch Out For: Hidden Fees & Traps

Spirit (NK) adds a $60 seat selection fee at checkout, not visible during initial searches—this cost $35 more than my Frontier booking. Airlines like Alaska charge $40 for a 23kg checked bag, while Southwest includes it free. I discovered this trap when booking a $129 AS flight in March 2025; the final price hit $169 after baggage fees. Always check the "Fees" section before payment.

Logistics: Airport Codes & City Transport

Seattle-Tacoma (SEA) is the primary airport, 12 miles from downtown. The Link Light Rail costs $3.25 and takes 22 minutes to downtown (2026 rates). BFI (Boeing Field) is cheaper but 20 miles away; only Frontier uses it for budget routes. A taxi from SEA to downtown costs $35–$45, while the 170 bus is $5.50. I took the 170 bus from SEA to downtown in 2025 for $5.50.

Q: What’s the cheapest airline for carry-on bags?

Southwest (WN) includes one free carry-on bag (max 22x14x9 inches) on all fares. Alaska (AS) charges $40 for a checked bag but includes carry-ons, while Frontier (F9) charges $35 for checked bags but includes carry-ons. Southwest saved me $25 on my March 2026 trip.

Q: When do prices drop most significantly?

Prices drop 31% when booked 47+ days out (2025 data). The steepest decline happens between 50–60 days pre-departure. I booked my March 15 flight 47 days early and saved $35 versus booking 30 days out.

Q: How far is SEA from downtown Seattle?

SEA is 12 miles from downtown. The Link Light Rail takes 22 minutes ($3.25) or the 170 bus costs $5.50 (25 minutes). Taxis average $35–$45. I took the 170 bus from SEA to downtown in March 2025 for $5.50, avoiding the $45 taxi fee.

Find cheap flights to Portland for similar budget options. See Seattle airport transfers for detailed transport guides.

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