Seattle to Denver BFI, SEA → DEN
Boeing Field International Airport (BFI), Seattle-Tacoma International Airport (SEA) → Denver International Airport (DEN)
The cheapest return found recently is $733 with SeaPort Airlines, 28 Oct – 14 Nov, found 3 days ago. The cheapest one-way found recently is $428 with SeaPort Airlines, 28 Oct, found 4 days ago.
Return
Not enough comparable prices yet for a usual return price.
Cheapest return found recently
$733
28 Oct – 14 Nov · SeaPort Airlines
Boeing Field International Airport (BFI) → Denver International Airport (DEN)
Leaves 8:05 p.m. · Return leaves 10:55 p.m. · 37 h 45 min of travel, both ways together
out 1 stop, back 2 stops
found 3 days ago
Cheapest nonstop return
None seen yet.
Found recently, and the cheapest we hold
$733 28 Oct – 14 Novfound 3 days agoSee prices for these dates
$172 3 Dec – 4 Decfound 5 days agoSee prices for these dates
What have prices looked like?
Over 25 days, 24 Sept to 18 Oct, the cheapest return we saw each day was $166 to $336.
At $733, the cheapest return found recently is above that range.
25 days is a short history, so treat this range as an early guide.
Those were the prices on those days, not today's.
Is this a good return price?
Not enough comparable prices yet: we hold return fares on 2 departure dates and need at least 3 to say what is usual.
Could nearby dates be cheaper?
We hold no other 17-night return fares leaving within 3 days of 28 Oct to compare.
Every date we hold
3 fares on 2 departure dates
See the chart as a table
| Dates | From | Airline | Airports | Stops | Found | |
|---|---|---|---|---|---|---|
| 28 Oct – 14 Nov | $214 | Alaska Airlines | Seattle-Tacoma International Airport (SEA) → Denver International Airport (DEN) | out nonstop, back 1 stop | found 4 days ago | See prices for these dates |
| 3 Dec – 4 Dec | $172 | Frontier Airlines | Seattle-Tacoma International Airport (SEA) → Denver International Airport (DEN) | out 1 stop, back nonstop | found 5 days ago | See prices for these dates |
Which month looks cheapest?
December 2026 is the cheapest month — from $172.
Airlines on the cheapest dates: Alaska Airlines, Frontier Airlines.
One-way
The cheapest one-way fare on each of 6 departure dates is usually $95 to $157.
Cheapest one-way found recently
$428
28 Oct · SeaPort Airlines
Boeing Field International Airport (BFI) → Denver International Airport (DEN)
Leaves 8:05 p.m. · 20 h 58 min trip
2 stops
found 4 days ago
Cheapest nonstop one-way
$79
7 Nov · Frontier Airlines
Seattle-Tacoma International Airport (SEA) → Denver International Airport (DEN)
Leaves 4:27 p.m. · 2 h 48 min trip
nonstop
found 5 days ago
Found recently, and the cheapest we hold
$428 28 Octfound 4 days agoOpen this trip
$79 7 Novfound 5 days agoOpen this trip
What have prices looked like?
Over 25 days, 24 Sept to 18 Oct, the cheapest one-way we saw each day was $31 to $104.
At $428, the cheapest one-way found recently is above that range.
25 days is a short history, so treat this range as an early guide.
Those were the prices on those days, not today's.
Is this a good one-way price?
Compared with the cheapest one-way fare on each of 6 departure dates from 28 Oct to 8 Nov, found by travelers' searches in the last 7 days (economy, the price the seller showed on Aviasales). The usual range is the middle half of those prices.
Could nearby dates be cheaper?
We hold no other one-way fares leaving within 3 days of 28 Oct to compare.
Every date we hold
10 fares on 6 departure dates
See the chart as a table
| Dates | From | Airline | Airports | Stops | Found | |
|---|---|---|---|---|---|---|
| 28 Oct | $428 | SeaPort Airlines | Boeing Field International Airport (BFI) → Denver International Airport (DEN) | 2 stops | found 4 days ago | Open this trip |
| 1 Nov | $163 | Frontier Airlines | Seattle-Tacoma International Airport (SEA) → Denver International Airport (DEN) | 1 stop | found 5 days ago | Open this trip |
| 5 Nov | $112 | Frontier Airlines | Seattle-Tacoma International Airport (SEA) → Denver International Airport (DEN) | 1 stop | found 5 days ago | Open this trip |
| 6 Nov | $89 | Frontier Airlines | Seattle-Tacoma International Airport (SEA) → Denver International Airport (DEN) | nonstop | found 5 days ago | Open this trip |
| 7 Nov | $79 | Frontier Airlines | Seattle-Tacoma International Airport (SEA) → Denver International Airport (DEN) | nonstop | found 5 days ago | Open this trip |
| 8 Nov | $137 | United Airlines | Seattle-Tacoma International Airport (SEA) → Denver International Airport (DEN) | nonstop | found 5 days ago | Open this trip |
Which month looks cheapest?
November 2026 is the cheapest month — from $79.
Airlines on the cheapest dates: Frontier Airlines, SeaPort Airlines, United Airlines.
Premium cabin fares from Seattle to Denver
We hold no premium economy, business or first-class fares for this route: we collect them for the busiest routes, and this one is not among them yet.
Today's prices for 28 Oct – 14 Nov in another cabin: Premium economy · Business · First
Today's prices for 28 Oct in another cabin: Premium economy · Business · First
How far ahead were prices cheapest for Seattle to Denver?
Return
Fares 30 to 59 days before departure were typically 47% lower than 0 to 6 days before departure.
From the cheapest return each day between 24 Sept and 18 Oct (25 days), grouped by how many days ahead the flight left; one adult in economy.
Each range covers different departure dates, so this compares typical fares, not the same trip priced twice.
Prices reflect recent searches — current fares may differ.
See these ranges as a table
| Booked ahead by | Typical fare | Cheapest day | Above the cheapest | Days of prices |
|---|---|---|---|---|
| 0–6 days | $352 | $166 | +87% | 9 |
| 7–13 days | $328 | $214 | +75% | 8 |
| 14–29 days | $676 | $261 | +260% | 10 |
| 30–59 days | $188 | $172 | Cheapest seen | 13 |
| 60–89 days | $188 | $188 | +0% | 11 |
| 180+ days | $336 | $336 | +79% | 15 |
One-way
Fares 14 to 29 days before departure were typically 58% lower than 7 to 13 days before departure.
From the cheapest one-way each day between 24 Sept and 18 Oct (25 days), grouped by how many days ahead the flight left; one adult in economy.
Each range covers different departure dates, so this compares typical fares, not the same trip priced twice.
Prices reflect recent searches — current fares may differ.
See these ranges as a table
| Booked ahead by | Typical fare | Cheapest day | Above the cheapest | Days of prices |
|---|---|---|---|---|
| 7–13 days | $114 | $114 | +138% | 8 |
| 14–29 days | $48 | $31 | Cheapest seen | 15 |
| 30–59 days | $50 | $47 | +4% | 20 |
| 60–89 days | $153 | $153 | +219% | 8 |
| 90–179 days | $117 | $117 | +144% | 8 |
Could a nearby airport be cheaper?
A different airport at either end can change the fare — sometimes a lot.
Return
Everett → Denver
34 km from Seattle
$398
$335 less than flying from Seattle
28 Oct – 14 Nov · PAE → DEN · out 1 stop, back nonstop
found 3 days ago
Cheapest recent price on each route — round trip, per traveler in Economy. Distances are in a straight line.
One-way
Everett → Denver
34 km from Seattle
$472
$44 more than flying from Seattle
28 Oct · PAE → DEN · 1 stop
found 4 days ago
Cheapest recent price on each route — one way, per traveler in Economy. Distances are in a straight line.
Live price for these dates
The cheapest return found recently is for 28 Oct – 14 Nov. A live search on this page shows what those dates cost now, for one adult in economy.
Prices are what travelers' searches on Aviasales found in the last 7 days, in US dollars: the price the seller showed on Aviasales; bags may cost extra. Fares change, so check today's price before you book. How our prices work