Cheapest Day to Buy Flights from San Francisco to Boston
Low Fare Calendar — San Francisco to Boston
When to book vs. when to fly — San Francisco → Boston
Live data from recent Aviasales searches for SFO → BOS, plus a booking rule of thumb.
Lowest indicative per-adult round-trip fares seen in Aviasales searches — confirmed live on the booking site before payment.
See the cheapest month’s fares ↗Search any date — San Francisco → Boston
Flight options — San Francisco → Boston
Recently-seen round-trip fares — click any flight for details, alternatives and booking.
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FAQ — SFO → BOS
How much is a flight from San Francisco to Boston?
Prices vary by season and departure day. The Low Fare Calendar on this page shows the cheapest fare for every day of the coming year between San Francisco (SFO) and Boston (BOS).
Which airlines fly from San Francisco to Boston?
The San Francisco → Boston route covers about 4,341 km and commonly 8–12 h nonstop or with 1 stop. Multiple carriers operate it — search FlyTiming to compare every airline and agency serving SFO → BOS in one search.
What is the cheapest day to fly from San Francisco to Boston?
It varies by month. The price card on this page highlights the cheapest month and the historically cheapest day of the week to fly this route — the Low Fare Calendar below marks low-fare days in green.
When is the best time to book flights from San Francisco to Boston?
As a rule of thumb, fares on international routes are usually lowest roughly 3–12 weeks before departure — and northern-summer peak (June–August) usually means the highest fares — book early or aim for the shoulder months. The calendar below is the fastest way to spot the cheapest months for San Francisco → Boston.