BOS to SJU flight delays & on-time performance
Nonstop flights from Boston Logan International Airport to Luis Munoz Marin International Airport · 1,674 miles · Aug 2025 – Jul 2026
No FAA-reported ground stops or delays at BOS or SJU right now. Individual flights can still be delayed by the airline; check with your airline for your flight.
Key facts
- Flights from Boston (BOS) to San Juan (SJU) arrived on time 67% of the time in Aug 2025 – Jul 2026, worse than the 78% national average.
- 2.9% were cancelled, and 12% arrived an hour or more late.
- Delta Air Lines was the most punctual airline here (75% on time); Spirit Airlines was the least (53%).
- Departures scheduled around 6am did best (82% on time); around 9pm did worst (29%).
- Tuesday was the most reliable day to fly (73% on time) and Sunday the least (63%).
- The largest source of delay minutes was air traffic control & airport congestion (35%).
Which airline is most on time from BOS to SJU?
Ranked by on-time arrival rate. Regional airlines fly under their partner's brand (e.g. SkyWest for Delta Connection or United Express).
| Airline | On time | Cancelled | Avg delay | 1 hr+ late | Flights |
|---|---|---|---|---|---|
| Delta Air Lines | 75% | 1.5% | 16 min | 5.9% | 398 |
| JetBlue | 67% | 2.8% | 25 min | 13.1% | 1,192 |
| Spirit Airlines | 53% | 8.2% | 51 min | 20.9% | 146 |
| Frontier Airlines | 42% | 2.9% | 67 min | 33.3% | 34 |
Best time of day to fly
On-time arrival rate by scheduled departure hour (local time).
- 5am78%79 flights
- 6am82%66 flights
- 7am76%81 flights
- 8am79%501 flights
- 9am63%64 flights
- 10am57%121 flights
- 11am74%38 flights
- 12pm69%163 flights
- 1pm66%85 flights
- 2pm46%38 flights
- 3pm59%105 flights
- 5pm67%88 flights
- 6pm59%105 flights
- 7pm34%39 flights
- 8pm51%78 flights
- 9pm29%56 flights
- 10pm68%46 flights
Best day of the week
On-time arrival rate by day of departure.
- Monday66%6.6% cancelled
- Tuesday73%2.5% cancelled
- Wednesday72%2.6% cancelled
- Thursday63%0.8% cancelled
- Friday69%1.2% cancelled
- Saturday67%3.8% cancelled
- Sunday63%3.0% cancelled
On-time trend by month
Why flights are late
Share of delay minutes by cause, as reported by airlines to the DOT.
- Air traffic control & airport congestion35%
- Late-arriving aircraft32%
- Airline (crew, maintenance, cleaning, fueling)30%
- Extreme weather2%
- Security0%
Why flights are cancelled
Share of cancellations by reason.
- Extreme weather38%
- Airline (crew, maintenance, cleaning, fueling)31%
- Air traffic control & airport congestion27%
- Security4%
BOS to SJU: common questions
- How often are BOS to SJU flights on time?
- 67% of flights arrived less than 15 minutes late in Aug 2025 – Jul 2026, compared with 78% for all US flights.
- How often are flights from Boston to San Juan cancelled?
- 2.9% of scheduled flights were cancelled (52 of 1,770).
- How long are typical delays?
- Across all flights the average arrival delay was 25 min (early arrivals count as zero). Flights that were late arrived 74 min behind schedule on average, and 12.5% of flights were an hour or more late.
- How long is taxi time at BOS?
- Flights on this route spent 21 min taxiing from the gate to takeoff on average.
Related routes
Return trip: SJU to BOS — 71% on time
More flights from Boston
Data: U.S. DOT Bureau of Transportation Statistics, Aug 2025 – Jul 2026 (12 months). Latest month published by BTS: July 2026. Route: BOS → SJU, nonstop flights by US airlines that report to the DOT. How we calculate this.