San Juan to Boston

What the Data Says About SJU to BOS

The San Juan to Boston corridor (SJU → BOS) covers roughly 1,674 miles and is served by 16 carriers, based on Bureau of Transportation Statistics reporting. Across 10,011 flights in the dataset, this route posts a 72.9% on-time rate with an average delay of 80.9 minutes when flights run late. Over the most recent 24 months of BTS data, 4,179 flights were recorded on this pairing — 49 cancelled (1.2%) and 17 diverted (0.4%). Those baseline metrics tell you what to expect before you book.

Having 16 carriers on the route matters: more carriers generally means more daily schedule options, competitive pricing, and redundancy when flights are cancelled. With 10,011 total flights analyzed, the 72.9% on-time figure is statistically meaningful rather than a small-sample fluke. The 80.9-minute average delay applies only to flights that actually ran late, so it is not the average wait across all departures — the majority of flights on this route depart on time under the BTS definition of a delay (15+ minutes past schedule).

Looking at recent months, Jun 2025 posted the best performance on this corridor at 85% on-time, while Aug 2025 came in at 67% on-time — a 18-point gap between best and worst recent month. For travelers evaluating the SJU to BOS route, the combination of a 72.9% on-time rate, 80.9-minute average delay, 1.2% recent cancellation rate, and 16 available carriers is the concrete summary of what BTS data shows about reliability on this pairing.