SFO to BOS flight delays
San Francisco, CA (SFO) Boston, MA (BOS) · 2,704 miles
502 flights · March 2025 – August 2026 · US Bureau of Transportation Statistics
68.88%
Arrived on time
Within 15 minutes of schedule
0.8%
Cancelled
Share of scheduled flights
68 min
When late, late by
Average across delayed arrivals
22 min
Delay per flight
Averaged over every flight flown
What the record says about this route
Which airline you fly changes the odds here. United Airlines arrived on time 20.8 points more often than JetBlue Airways over the same period on the same route — same airports, same weather, same air traffic control. A gap that survives all of that is about how the two airlines are run.
The two directions do not behave alike. BOS to SFO arrives on time 12.4 points less often than the outbound. Delay accumulates through the flying day, so whichever direction is scheduled later tends to carry the worse record — which is an argument for booking the morning departure if the choice exists.
Flights from San Francisco to Boston run late more often than the average route, though not severely.
This is a thin route — 502 flights across the whole period. On a route this infrequent a cancellation is far more costly than the rate suggests, because the next departure may not be the same day.
Which airline should you fly on this route?
Over March 2025 – August 2026, United Airlines arrived on time most often on SFO to BOS. JetBlue Airways was late most often.
Every airline on SFO to BOS
Ranked by how many flights each one operated. A carrier with fewer than 100 flights in the period is listed but not graded.
| Airline | Flights | On time | Cancelled | Avg delay | Grade |
|---|---|---|---|---|---|
| JetBlue Airways | 203 | 61.19% | 0.99% | 81 min | D |
| United Airlines | 201 | 82% | 0.5% | 54 min | B |
| Delta Air Lines | 98 | 57.73% | 1.02% | 57 min | — |
The return leg
BOS to SFO Boston back to San Francisco 56.45% on time FOther routes from San Francisco
What these figures do and do not tell you
Everything on this page is counted from the flights that actually operated on SFO to BOS during March 2025 – August 2026, as reported by the airlines to the US Bureau of Transportation Statistics. "On time" is the federal definition: arriving at the gate within 15 minutes of the scheduled time.
A route's record is a description of the past, not a forecast. Weather, air traffic control and the aircraft's earlier flights that day drive most delays, and none of them are predictable from a historical rate. What the record does tell you is whether this route runs late more often than others, and which carrier on it has the better history — which is the part you can actually act on when you book.
Cancellations are counted separately from delays because they are a different problem for a traveller: a late flight still gets you there. How the grade is calculated →