Route Reliability
Boston → San Juan
BOS–SJU · 1,674 miles · Boston Logan International Airport to Luis Muñoz Marín International Airport
- 70%
- Arrive within 15 minutes
- 16 min
- Average arrival delay
- 2.6%
- Cancelled
- 1,853
- Flights in the data
Data through May 2026.
Who flies it best
Ranked by on-time arrivals. Historical results, not predictions.
- 1.Delta Air Lines77%398 flights
- 2.JetBlue Airways70%1,260 flights
- 3.Spirit Airlines57%161 flights
Not enough history to rank: Frontier Airlines (34 flights). We rank airlines only after 100 flights on the route.
What the data says
Morning-you made the right choice.
BOS–SJU flights departing between 6–9 AM arrived on time 80% of the time, versus 58% between 6–9 PM.
Sunday scaries are real for this one.
BOS–SJU flights arrived on time 74% of the time on Tuesdays. On Sundays: 66%.
Delta Air Lines has a clear lead on this route.
Delta Air Lines arrived on time 77% of the time on this route; Spirit Airlines managed 57%.
Trending in the right direction.
BOS–SJU flights arrived on time 73% of the time over the last three months in the data, compared with 59% in the three months before that.
Best historical flights
Ranked by on-time arrivals, minimum 100 flights. Past performance, not a promise.
Top flights by on-time rate
More flights on this route
The breakdown
- Mon67%(257 flights)
- Tue74%(232 flights)
- Wed74%(225 flights)
- Thu68%(281 flights)
- Fri73%(263 flights)
- Sat70%(265 flights)
- Sun66%(278 flights)
- 3–6 AM78%(73 flights)
- 6–9 AM80%(634 flights)
- 9 AM–12 PM69%(242 flights)
- 12–3 PM67%(339 flights)
- 3–6 PM64%(177 flights)
- 6–9 PM58%(269 flights)
- 9 PM–12 AM58%(67 flights)
Jun 81% → May 79% on time
| Month | On-time percentage | Flights |
|---|---|---|
| June 2025 | 81% | 160 |
| July 2025 | 80% | 170 |
| August 2025 | 74% | 178 |
| September 2025 | 70% | 83 |
| October 2025 | 72% | 93 |
| November 2025 | 73% | 109 |
| December 2025 | 59% | 169 |
| January 2026 | 60% | 151 |
| February 2026 | 58% | 165 |
| March 2026 | 68% | 197 |
| April 2026 | 72% | 186 |
| May 2026 | 79% | 140 |
Keep nerding
Based on 1,853 historical flights, because apparently we checked. Historical flight data: U.S. Bureau of Transportation Statistics, June 2025 – May 2026. Data through May 2026. How we calculate this.