AirSource

Flights San Francisco → Seattle — September 21, 2026

One way · Economy · 1 adult · price per person

The cheapest itinerary observed for Monday, September 21, 2026 on the San Francisco–Seattle route: 1 stop itinerary (2 flights) via Los Angeles International (LAX), from San Francisco International (SFO) to Seattle-Tacoma (SEA), first flight Frontier Airlines F92858, departs 12:07 PM, arrives 6:36 PM, total travel time 6h 29m including layovers, flight time 4h 37m (layovers excluded), $132 per person. Fare as listed by Aviasales: carry-on bag not included (personal item only), checked bag not included, changes not allowed, non-refundable. Price found in an Aviasales search on September 7, 2026 and read by AirSource on September 10, 2026, 20:48 UTC: it is not guaranteed and is confirmed on Aviasales at booking time. The cheapest direct flight observed: Alaska Airlines AS758, from San Francisco International (SFO) to Seattle-Tacoma (SEA), departs 6:21 PM, arrives 8:32 PM, direct, 2h 11m, $169 per person. Fare as listed by Aviasales: carry-on bag included, checked bag not included, changes not allowed, non-refundable.

Lowest price observed in the available data

1-stop itinerary (2 flights)

via Los Angeles International (LAX) · first flight Frontier Airlines F92858

1 stop
Mon, Sep 21
San Francisco International (SFO)
6h 29m
1 stop
Mon, Sep 21
Seattle-Tacoma (SEA)
First flight
Frontier Airlines F92858 (1st of 2 flights)
Connecting flights
Operated after the layover in Los Angeles International (LAX); airline and flight number are not provided by Aviasales in this record: see them on the booking site.
Departure
San Francisco International (SFO) · September 21, 2026 · local time (UTC-7)
Final arrival
Seattle-Tacoma (SEA) · September 21, 2026 · local time (UTC-7)
Stops
1 stop · in Los Angeles International (LAX)
Total travel time
6h 29m (layovers included)
Flight time
4h 37m (layovers excluded)
Layover time
1h 52m
Carry-on bag
not included (personal item only)
Checked bag
not included
Changes
not allowed
Refund
non-refundable
Last observed price
$132 per person, one way
Observed
Price and fare conditions found in an Aviasales search on · read by AirSource on · more than 48 hours ago
Last observed price
$132
per person, one way
Check the current price and book

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Price not guaranteed: it is confirmed on Aviasales at booking time. How it works

Cheapest direct flight observed

Alaska Airlines AS758

Direct · San Francisco International (SFO) → Seattle-Tacoma (SEA)

Direct
Mon, Sep 21
San Francisco International (SFO)
2h 11m
direct
Mon, Sep 21
Seattle-Tacoma (SEA)
Airline
Alaska Airlines (AS)
Flight
AS758
Departure
San Francisco International (SFO) · September 21, 2026 · local time (UTC-7)
Arrival
Seattle-Tacoma (SEA) · September 21, 2026 · local time (UTC-7)
Stops
Direct (no plane change, as stated by the source; it can include a stop)
Duration
2h 11m
Carry-on bag
included
Checked bag
not included
Changes
not allowed
Refund
non-refundable
Last observed price
$169 per person, one way
Observed
Price and fare conditions found in an Aviasales search on · read by AirSource on · more than 48 hours ago
Last observed price
$169
per person, one way
Check the current price and book

Affiliate link. Booking, payment and support are handled by the seller you choose on Aviasales.

Price not guaranteed: it is confirmed on Aviasales at booking time. How it works

Looking for other times? All San FranciscoSeattle flights on September 21, 2026 on Aviasales.

Nearby dates