Carrier route record
B6BOS→SJU
JetBlue Airways · Boston to San Juan
- Flights
- 1,142
- Period
- September 2025 to August 2026
- Share of route
- 67%
- Carriers
- 4
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with JetBlue Airways.
JetBlue on BOS to SJU draws a C. About one flight in three arrives at least 15 minutes late, and the typical late arrival is a little over an hour behind schedule. Build slack into anything you connect to. That rests on 1,142 flights, with a median arrival 1 minute late.
The national on-time rate over the same period is 77.3%, so JetBlue on BOS to SJU runs 11 points behind the country as a whole. Across a thousand flights that is about 108 extra late arrivals.
Key figures
On time
66.5%
Arrivals under 15 minutes late, of 1,108 completed flights
Avg delay
73 min
Across delayed arrivals only, not all flights
Cancelled
2.80%
National rate is 1.89%
Whole route
66.8%
Every carrier on BOS to SJU, 1,717 flights
These figures cover 1,142 flights between September 2025 and August 2026. Beyond the headline rate, 13.6% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
Fare search by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Carrier by carrier
JetBlue against every carrier on BOS to SJU
JetBlue flew 1,142 of the 1,717 flights on BOS to SJU, most of the route. Its 66.5% on time is about level with the route as a whole at 66.8%. Ranked by on-time rate it is number two of four carriers on the route, where the range runs from Delta at 74.5% to Frontier at 42.4%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines | 398 | 74.5% | 57 min | 1.51% | C |
| JetBlue Airways (this page) | 1,142 | 66.5% | 73 min | 2.80% | C |
| Spirit Airlinesthin sample | 143 | 52.7% | 108 min | 8.39% | F− |
| Frontier Airlinesthin sample | 34 | 42.4% | 113 min | 2.94% | F |
Flight by flight
JetBlue flight numbers on BOS to SJU
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Departure window
When JetBlue runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 35 points, against half a point between the best and worst carrier.
- 5am–8am247 flights80.8%
- 8am–11am255 flights70.8%
- 11am–2pm196 flights72.0%
- 2pm–5pm56 flights49.1%
- 5pm–8pm217 flights61.6%
- 8pm–5am171 flights45.5%
Scale runs 35% to 85%.
The 8pm–5am window is where this operation falls apart: 45.5% on time, against 80.8% for the 5am–8am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 8am–11am window is the busiest, with 255 flights scheduled in it.
Across the year
JetBlue on BOS to SJU through the year
July is the worst month at 52.9% on time, 24 points below April, the best at 77.1%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. March was the busiest month here, with 124 flights.
Across the week, Tuesday is the strongest day at 74.7% on time and Thursday the weakest at 60.6%, a spread of 14 points.
Arrival by arrival
How late JetBlue on BOS to SJU runs when it is late
The 371 late arrivals split 83 under half an hour, 137 between 30 and 60 minutes, and 151 an hour or more.
- 15+ min early248 flights22.4%
- Within 15 min489 flights44.1%
- 15–29 min late83 flights7.5%
- 30–59 min late137 flights12.4%
- 1–2 hours late91 flights8.2%
- 2+ hours late60 flights5.4%
Scale runs 0% to 100%.
Share of 1,108 completed flights by arrival against schedule.
51 of 339 late departures made up the time and arrived on time, 15% of them. In the other direction, 83 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at SJU.
The worst days
Worst days for JetBlue on BOS to SJU
The latest arrival of the period was on 21 February 2026, 7 hours 44 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The same cause led on three of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 21 February 2026 | 7 hours 44 minutes | Late-arriving aircraft |
| 19 July 2026 | 6 hours 38 minutes | Carrier |
| 4 March 2026 | 5 hours 58 minutes | Late-arriving aircraft |
| 9 August 2026 | 5 hours 56 minutes | National Airspace System |
| 9 July 2026 | 5 hours 19 minutes | Late-arriving aircraft |
Delay causes
Why JetBlue runs late on this route
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 27,000 reported delay minutes.
- 42%Late-arriving aircraft
- 28%National Airspace System
- 27%Carrier
- 3%Extreme weather
- 0%Security
42% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 27,000 reported delay minutes here, that single category outweighs weather by 16 to one. The split is drawn from 27,156 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 80.8% on time here.
Cancellations run at 2.80%, against 1.89% nationally. That is roughly one flight in 40 cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.
Connections and stage length
What a delay here costs
13.6% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.
At 1,674 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
The return leg runs 68.5% on time across 1,342 flights, within 2 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
The sample behind these figures is 1,142 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
What to do with this
Booking JetBlue on BOS to SJU
Put together: the delay figures matter less here than the 2.80% cancellation rate. A late arrival costs you a little over an hour; a cancelled flight costs you the day. Book the 5am–8am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 1,108 completed flights over 12 months sit behind that.
Related
Where to go next
- BOS to SJU, every carrier
- JetBlue on SJU to BOS, the return leg
- Delta Air Lines on BOS to SJU74.5%
- Spirit Airlines on BOS to SJU52.7%
- JetBlue Airways network-wide record
- Boston Logan International (BOS) delay statistics
- Luis Munoz Marin International (SJU) delay statistics
- The US routes with the most cancellations
- Why the first flight of the morning is statistically safest
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.