BOS (Boston) to SJU (San Juan) flights arrive on time 70% of the time. The most reliable airline on this route is Delta Air Lines at 81%. The average delay is 74 minutes. Delays on this route are most often caused by the airline (crew, maintenance, or boarding).
Source: Bureau of Transportation Statistics. Updated May 2026.BOS → SJU
BOS (Boston) to SJU (San Juan)
BOS → SJU on-time performance by month
24
25
JanFebMarAprMayJunJulAugSepOctNovDec
Worse
Better
This route is delayed fairly often. About 70% of flights arrive on schedule.
Delays on this route are most often caused by the airline (crew, maintenance, or boarding).
Accurate?
Delta Air Lines is significantly more reliable on this route at 81% on time vs Frontier Airlines at 46%.
Airline Comparison
Delta Air Lines leads at 81% on time; Frontier Airlines trails at 46%.
Accurate?
Good to know
Departing from BOS
79% on timeExpect ~19 min sitting on the taxiway after your gate pushes back. BOS has long runway queues.
TSA is currently ~21 min. Best time: 4 AM (about 5 min).
Arriving at SJU
75% on timeWhen flights into SJU are late, the average delay is 75 minutes. Build buffer if you have ground plans.
If connecting at SJU: TSA is ~19 min right now. Allow at least 60 minutes for a domestic connection.
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Data last updated May 2026. Source: Bureau of Transportation Statistics.