Route · BOS → SJU · 2020–2025 BTS data
Boston to San Juan
According to PlainFlights' route traffic ranking (BTS On-Time Performance total flights), BOS to SJU (Boston to San Juan) ranks #1221 of 4927 tracked domestic routes by total flights (most flights = #1).
Data updated 2026-06-13
- 69.5%
- On-time
- -9.5 pts
- vs US avg
- 73 min
- Delay when late
- 9,566
- Flights
- #1221 of 4927
- Corpus placement
Cancelled
1.1%
Best Month
Sep 2024 85%
Worst Month
Dec 2024 54%
Distance
1,674 mi
Carriers
16
Monthly Performance
Recent 24 months of route data.
| Period | Flights | Delayed | Cancelled | Diverted | Carriers |
|---|---|---|---|---|---|
| Dec 2025 | 170 | 70 | 1 | 0 | DL,F9,NK,B6 |
| Nov 2025 | 110 | 29 | 1 | 0 | DL,B6 |
| Oct 2025 | 95 | 26 | 1 | 1 | B6,DL |
| Sep 2025 | 83 | 25 | 0 | 0 | DL,B6 |
| Aug 2025 | 181 | 48 | 2 | 1 | NK,B6,DL |
| Jul 2025 | 175 | 34 | 5 | 0 | B6,NK,DL |
| Jun 2025 | 160 | 31 | 0 | 0 | B6,DL,NK |
| May 2025 | 151 | 36 | 0 | 0 | B6,DL,F9,NK |
| Apr 2025 | 193 | 58 | 0 | 2 | DL,F9,NK,B6 |
| Mar 2025 | 212 | 62 | 1 | 2 | B6,NK,DL,F9 |
| Feb 2025 | 187 | 76 | 2 | 2 | B6,DL,F9,NK |
| Jan 2025 | 180 | 61 | 3 | 1 | B6,NK,DL,F9 |
| Dec 2024 | 185 | 86 | 0 | 0 | B6,DL,F9,NK |
| Nov 2024 | 150 | 52 | 1 | 1 | B6,DL,F9 |
| Oct 2024 | 116 | 29 | 1 | 0 | DL,F9,B6 |
| Sep 2024 | 117 | 18 | 1 | 1 | B6,DL,F9 |
| Aug 2024 | 222 | 100 | 6 | 0 | B6,DL,F9,NK |
| Jul 2024 | 230 | 78 | 4 | 0 | B6,DL,F9,NK |
| Jun 2024 | 212 | 67 | 2 | 1 | B6,DL,F9,NK |
| May 2024 | 162 | 41 | 3 | 0 | B6,DL,NK |
| Apr 2024 | 171 | 38 | 3 | 0 | B6,DL,NK |
| Mar 2024 | 163 | 47 | 1 | 0 | B6,DL,NK |
| Feb 2024 | 156 | 60 | 3 | 0 | B6,DL,NK |
| Jan 2024 | 156 | 52 | 1 | 0 | B6,DL,NK |
BOS–SJU seasonal on-time pattern
Best: October (74.8%) · weakest: December (62.2%)
Strongest calendar month
October
74.8% on-time · ~108 flights/mo
Busiest calendar month
July
~165 flights/mo avg
Weakest calendar month
December
62.2% on-time · ~144 flights/mo
Cancellation Rate
1.1%
42 of 3,937 flights
Diversion Rate
0.3%
12 of 3,937 flights
Explore origin & destination
On-time and delay data for the airports this route connects.
BOS - Boston
Full on-time, delay-cause, and seasonal performance for Boston, MA.
BOS on-time profileSJU - San Juan
Full on-time, delay-cause, and seasonal performance for San Juan, PR.
SJU on-time profileCompare the two airports
See BOS and SJU side by side on delays, cancellations, and reliability.
Compare BOS vs SJUOrigin-hub reliability standing
Softer reliability from BOS
Among 60 routes leaving BOS, only 5 (including this one) clear below 75% on-time, while 6 stay ≥85% and 49 sit mid-band. Travelers comparing BOS options should weigh this 69.5% print against those peers · fleet on-time rank #4847 of 4927.
Similar routes
Other BTS-tracked routes with comparable performance or trip length to BOS–SJU.
Routes with a similar on-time rate
What the Data Says About BOS to SJU
On-time performance on the BOS to SJU pairing (Boston to San Juan) trails a chunk of the network: 69.5% of 9,566 tracked flights arrived on schedule, with a 73.3-minute average delay on the ones that ran late. The route spans about 1,674 miles across 16 carriers. Cancellations over the trailing 24 months hit 1.1% (42 of 3,937 flights), with 0.3% diverted.
The monthly split is wide on this route: Sep 2024 posted the strongest performance at 85% on-time, while Dec 2024 came in at just 54% - a 31-point swing worth factoring into travel timing.
On the multi-year calendar, BOS–SJU peaks in October at 74.8% on-time while July carries the heaviest traffic (~165 flights per month) ; the softest month is December at 62.2%, a 12.6-point swing that repeats because the corridor's weather and holiday mix stays stable year to year.
Frequently Asked Questions
Where does BOS to SJU rank among US routes by traffic? ▼
How often are flights delayed from BOS to SJU? ▼
What is the cancellation rate for BOS to SJU? ▼
How far is the flight from BOS to SJU? ▼
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Airports on this route
Data source
Data Source: Bureau of Transportation Statistics (BTS), On-Time Performance Data. Statistics reflect cumulative performance across all available reporting periods.
Read our methodology - how this data is sourced, computed, and verified.
Using BOS–SJU data
BOS–SJU sits 9.5 pts below the national 79% average; check the seasonal chart and airport profiles before treating the headline as typical.
- Compare BOS and SJU airport profiles: delay causes and top routes differ even on the same corridor. BOS airport
- If your dates flex, October (74.8% on-time) beats December (62.2%) on this corridor. Seasonal chart
- 4 other routes post a similar 69.5% on-time rate; compare before you commit to this pairing. Similar routes
On-time rate reflects the BTS historical average across all reporting carriers on this origin–destination pair, not any single flight or booking recommendation.
Every figure on PlainFlights is rendered directly from BTS On-Time Performance data, no number is typed in by an editor. This page aggregates this specific route's on-time performance and monthly trend, live from the dataset. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.