SJU to BOS flight delays & on-time performance
Nonstop flights from Luis Munoz Marin International Airport to Boston Logan International Airport · 1,674 miles · Aug 2025 – Jul 2026
No FAA-reported ground stops or delays at SJU or BOS right now. Individual flights can still be delayed by the airline; check with your airline for your flight.
Key facts
- Flights from San Juan (SJU) to Boston (BOS) arrived on time 71% of the time in Aug 2025 – Jul 2026, worse than the 78% national average.
- 3.1% were cancelled, and 11% arrived an hour or more late.
- Delta Air Lines was the most punctual airline here (77% on time); JetBlue was the least (69%).
- Departures scheduled around 5am did best (86% on time); around 7pm did worst (57%).
- Tuesday was the most reliable day to fly (76% on time) and Sunday the least (66%).
- The largest source of delay minutes was late-arriving aircraft (50%).
Which airline is most on time from SJU to BOS?
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 | 77% | 1.5% | 16 min | 5.7% | 398 |
| Spirit Airlines | 73% | 4.1% | 16 min | 11.6% | 145 |
| Frontier Airlines | 70% | 2.9% | 15 min | 6.1% | 34 |
| JetBlue | 69% | 3.5% | 25 min | 13.0% | 1,384 |
Best time of day to fly
On-time arrival rate by scheduled departure hour (local time).
- 2am83%25 flights
- 5am86%103 flights
- 6am75%200 flights
- 8am76%91 flights
- 10am83%80 flights
- 11am74%66 flights
- 12pm65%85 flights
- 1pm71%269 flights
- 2pm77%318 flights
- 3pm59%195 flights
- 4pm71%101 flights
- 5pm60%59 flights
- 6pm69%87 flights
- 7pm57%113 flights
- 8pm59%109 flights
Best day of the week
On-time arrival rate by day of departure.
- Monday70%5.4% cancelled
- Tuesday76%2.3% cancelled
- Wednesday71%1.6% cancelled
- Thursday68%0.7% cancelled
- Friday75%1.1% cancelled
- Saturday70%4.7% cancelled
- Sunday66%5.6% cancelled
On-time trend by month
Why flights are late
Share of delay minutes by cause, as reported by airlines to the DOT.
- Late-arriving aircraft50%
- Airline (crew, maintenance, cleaning, fueling)30%
- Air traffic control & airport congestion19%
- Extreme weather1%
- Security0%
Why flights are cancelled
Share of cancellations by reason.
- Extreme weather44%
- Air traffic control & airport congestion28%
- Airline (crew, maintenance, cleaning, fueling)25%
- Security3%
SJU to BOS: common questions
- How often are SJU to BOS flights on time?
- 71% 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 San Juan to Boston cancelled?
- 3.1% of scheduled flights were cancelled (61 of 1,961).
- How long are typical delays?
- Across all flights the average arrival delay was 22 min (early arrivals count as zero). Flights that were late arrived 73 min behind schedule on average, and 11.3% of flights were an hour or more late.
- How long is taxi time at SJU?
- Flights on this route spent 14 min taxiing from the gate to takeoff on average.
Related routes
Return trip: BOS to SJU — 67% on time
More flights from San Juan
Data: U.S. DOT Bureau of Transportation Statistics, Aug 2025 – Jul 2026 (12 months). Latest month published by BTS: July 2026. Route: SJU → BOS, nonstop flights by US airlines that report to the DOT. How we calculate this.