Boston to Seattle BOS → SEA
Logan International Airport (BOS) → Seattle-Tacoma International Airport (SEA)
The cheapest return found recently is $471 with Alaska Airlines, 25 Dec – 3 Jan 2027, found 4 days ago. The cheapest one-way found recently is $240 with Alaska Airlines, 15 Jun 2027, found yesterday.
Return
The cheapest return fare on each of 3 departure dates is usually $443 to $479.
Cheapest return found recently
$471
25 Dec – 3 Jan 2027 · Alaska Airlines
Logan International Airport (BOS) → Seattle-Tacoma International Airport (SEA)
Leaves 9:00 a.m. · Return leaves 3:35 p.m. · 12 h 2 min of travel, both ways together
out nonstop, back nonstop
found 4 days ago
Cheapest nonstop return
$471
25 Dec – 3 Jan 2027 · Alaska Airlines
Logan International Airport (BOS) → Seattle-Tacoma International Airport (SEA)
Leaves 9:00 a.m. · Return leaves 3:35 p.m. · 12 h 2 min of travel, both ways together
out nonstop, back nonstop
found 4 days ago
Found recently, and the cheapest we hold
$471 25 Dec – 3 Jan 2027found 4 days agoSee prices for these dates
$415 7 Jan 2027 – 11 Jan 2027found 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 $334 to $438.
At $471, 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?
Compared with the cheapest return fare on each of 3 departure dates from 25 Dec to 7 Jan 2027, 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?
No. We hold 9-night return fares on 1 other departure date within 3 days of 25 Dec, and it is not cheaper.
Every date we hold
4 fares on 3 departure dates
See the chart as a table
| Dates | From | Airline | Airports | Stops | Found | |
|---|---|---|---|---|---|---|
| 25 Dec – 3 Jan 2027 | $471 | Alaska Airlines | Logan International Airport (BOS) → Seattle-Tacoma International Airport (SEA) | out nonstop, back nonstop | found 4 days ago | See prices for these dates |
| 26 Dec – 4 Jan 2027 | $487 | Alaska Airlines | Logan International Airport (BOS) → Seattle-Tacoma International Airport (SEA) | out nonstop, back 1 stop | found 4 days ago | See prices for these dates |
| 7 Jan 2027 – 11 Jan 2027 | $415 | Alaska Airlines | Logan International Airport (BOS) → Seattle-Tacoma International Airport (SEA) | out 1 stop, back 1 stop | found 5 days ago | See prices for these dates |
Which month looks cheapest?
January 2027 is the cheapest month — from $415.
Airlines on the cheapest dates: Alaska Airlines.
One-way
The cheapest one-way fare on each of 4 departure dates is usually $235 to $241.
Cheapest one-way found recently
$240
15 Jun 2027 · Alaska Airlines
Logan International Airport (BOS) → Seattle-Tacoma International Airport (SEA)
Leaves 3:28 p.m. · 6 h 22 min trip
nonstop
found yesterday
Cheapest nonstop one-way
$240
15 Jun 2027 · Alaska Airlines
Logan International Airport (BOS) → Seattle-Tacoma International Airport (SEA)
Leaves 3:28 p.m. · 6 h 22 min trip
nonstop
found yesterday
Found recently, and the cheapest we hold
$240 15 Jun 2027found yesterdayOpen this trip
$227 31 May 2027found 5 days agoOpen this trip
What have prices looked like?
Over 19 days, 28 Sept to 18 Oct, the cheapest one-way we saw each day was $163 to $246.
19 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 4 departure dates from 24 May 2027 to 21 Jun 2027, 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 15 Jun 2027 to compare.
Every date we hold
4 fares on 4 departure dates
See the chart as a table
| Dates | From | Airline | Airports | Stops | Found | |
|---|---|---|---|---|---|---|
| 24 May 2027 | $238 | jetBlue | Logan International Airport (BOS) → Seattle-Tacoma International Airport (SEA) | nonstop | found 4 days ago | Open this trip |
| 31 May 2027 | $227 | jetBlue | Logan International Airport (BOS) → Seattle-Tacoma International Airport (SEA) | nonstop | found 5 days ago | Open this trip |
| 15 Jun 2027 | $240 | Alaska Airlines | Logan International Airport (BOS) → Seattle-Tacoma International Airport (SEA) | nonstop | found yesterday | Open this trip |
| 21 Jun 2027 | $242 | jetBlue | Logan International Airport (BOS) → Seattle-Tacoma International Airport (SEA) | nonstop | found yesterday | Open this trip |
Which month looks cheapest?
May 2027 is the cheapest month — from $227.
Airlines on the cheapest dates: jetBlue, Alaska Airlines.
Premium cabin fares from Boston to Seattle
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 25 Dec – 3 Jan 2027 in another cabin: Premium economy · Business · First
Today's prices for 15 Jun 2027 in another cabin: Premium economy · Business · First
How far ahead were prices cheapest for Boston to Seattle?
Return
The cheapest fares were 7 to 13 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 |
|---|---|---|---|---|
| 7–13 days | $353 | $334 | Cheapest seen | 16 |
| 14–29 days | $380 | $351 | +8% | 13 |
| 30–59 days | $424 | $412 | +20% | 17 |
| 60–89 days | $438 | $412 | +24% | 25 |
| 180+ days | $451 | $451 | +28% | 12 |
One-way
Not enough history yet: in 19 days of one-way prices, 28 Sept to 18 Oct, fewer than 3 booking ranges had prices on 7 days or more.
Could a nearby airport be cheaper?
A different airport at either end can change the fare — sometimes a lot.
Return
Boston → Victoria
119 km from Seattle
$553
$82 more than flying to Seattle
11 Jun 2027 – 19 Jun 2027 · BOS → YYJ · out 1 stop, back 1 stop
found today
Cheapest recent price on each route — round trip, per traveler in Economy. Distances are in a straight line.
Live price for these dates
The cheapest return found recently is for 25 Dec – 3 Jan 2027. 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