Cheap flights from Boston to San Francisco from $459 BOS → SFO
Logan International Airport (BOS) → San Francisco International Airport (SFO)
The cheapest return found recently is $459 with Frontier Airlines, 20 Nov – 27 Nov, found 2 days ago.
- Cheapest return found recently
- $459, 20 Nov to 27 Nov
- Usual return price
- $306 to $383
- Cheapest month to fly
- December 2026, return fares from $306 found in the last 7 days
Return
The cheapest return fare on each of 3 departure dates is usually $306 to $383.
Cheapest return found recently
$459
20 Nov – 27 Nov · Frontier Airlines
Logan International Airport (BOS) → San Francisco International Airport (SFO)
Leaves 8:36 a.m. · Return leaves 6:00 a.m. · 16 h 33 min of travel, both ways together
out 1 stop, back nonstop
found 2 days ago
Cheapest nonstop return
None seen yet.
Found recently, and the cheapest we hold
$459 20 Nov – 27 Novfound 2 days agoSee prices for these dates
$306 4 Dec – 7 Decfound 3 days agoSee prices for these dates
What have prices looked like?
Over 47 days, 24 Sept to 11 Nov, the cheapest return we saw each day was $237 to $645.
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 20 Nov to 10 Dec, 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 7-night return fares leaving within 3 days of 20 Nov to compare.
Every date we hold
4 fares on 3 departure dates
See the chart as a table
| Dates | From | Airline | Airports | Stops | Found | |
|---|---|---|---|---|---|---|
| 20 Nov – 27 Nov | $459 | Frontier Airlines | Logan International Airport (BOS) → San Francisco International Airport (SFO) | out 1 stop, back nonstop | found 2 days ago | See prices for these dates |
| 4 Dec – 7 Dec | $306 | Alaska Airlines | Logan International Airport (BOS) → San Francisco International Airport (SFO) | out 1 stop, back 1 stop | found 3 days ago | See prices for these dates |
| 10 Dec – 13 Dec | $306 | Alaska Airlines | Logan International Airport (BOS) → San Francisco International Airport (SFO) | out 1 stop, back 1 stop | found 7 days ago | See prices for these dates |
Which month looks cheapest?
December 2026 is the cheapest month — from $306.
Airlines on the cheapest dates: Alaska Airlines, Frontier Airlines.
Premium cabin fares from Boston to San Francisco
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 20 Nov – 27 Nov in another cabin: Premium economy · Business · First
How far ahead were prices cheapest for Boston to San Francisco?
Return
Fares 14 to 29 days before departure were typically 24% lower than 0 to 6 days before departure.
From the cheapest return each day between 24 Sept and 11 Nov (47 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 | $513 | $508 | +31% | 10 |
| 7–13 days | $645 | $396 | +65% | 7 |
| 14–29 days | $392 | $281 | Cheapest seen | 30 |
| 30–59 days | $400 | $237 | +2% | 35 |
| 90–179 days | $401 | $401 | +2% | 8 |
Could a nearby airport be cheaper?
A different airport at either end can change the fare — sometimes a lot.
Return
Boston → San Jose
67 km from San Francisco
$422
$37 less than flying to San Francisco
19 Dec – 18 Jan 2027 · BOS → SJC · out 2 stops, back nonstop
found 3 days ago
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 20 Nov – 27 Nov. A live search on this page shows what those dates cost now, for one adult in economy.
Questions about this trip
How much is a return flight from Boston to San Francisco?
The cheapest return found recently is $459 with Frontier Airlines, 20 Nov to 27 Nov, found 2 days ago. The cheapest return we hold, of any age, is $306 with Alaska Airlines, 4 Dec to 7 Dec, found 3 days ago. The cheapest return fare on each of 3 departure dates is usually $306 to $383.
What is the cheapest month to fly from Boston to San Francisco?
December 2026 is the cheapest month for a return, from $306, 4 Dec to 7 Dec, found 3 days ago.
How far ahead should I book a flight from Boston to San Francisco?
In 47 days of prices between 24 Sept and 11 Nov, return fares 14 to 29 days before departure were typically 24% lower than 0 to 6 days before departure.
Which airlines have the cheapest flights from Boston to San Francisco?
Between 20 Nov and 10 Dec, Alaska Airlines has the cheapest return on 2 of the 3 departure dates we hold, and Frontier Airlines on 1.
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