Cheap flights from Boston to San Francisco
Cheapest current fares: $153 in June 2026, 4,341 km direct flight in ~5h 6m.
Cheapest month-by-month fares
Lowest available fare per calendar month from Boston (BOS) to San Francisco (SFO). Refreshed daily.
Boston (BOS) → San Francisco (SFO)
- June 2026 $153
- May 2026 $157
- July 2026 $161
- August 2026 $174
Frequently asked questions
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What is the cheapest month to fly from Boston to San Francisco?
Based on current 6-month forward fare data, June 2026 is the cheapest month to fly from Boston (BOS) to San Francisco (SFO), with fares starting from $153.
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What is the lowest current fare from BOS to SFO?
The lowest currently-listed fare from Boston (BOS) to San Francisco (SFO) is $153 on 2026-06-16.
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How long is the flight from Boston to San Francisco?
Direct flights from BOS to SFO cover approximately 4,341 km (2,697 miles), with an estimated flight time of 5h 6m. Operating airlines: B6, DL, UA.
Related guides for this route
Sibling pages — full route detail, airport overviews, visa context, per-airline routes.