Itineraries flown on 20+ days in the Jun 6 – Jul 31, 2026 schedule · each leg’s record Aug 2025 – Jul 2026

No clear winner: airlines and hours on this route all land within a few points of 72% on time.

Nonstops


Delta	SJU	BOS	4h 23m	78%	1.5%	398	Flying now
JetBlue	SJU	BOS	4h 08m	70%	3.5%	1,384	Flying now
Spirit	SJU	BOS	4h 24m	74%	4.1%	145	Not flying now
Frontier	SJU	BOS	4h 19m	70%few flights	2.9%	34	Not flying now

Best connections, one ticket

Most reliable Quickest (80%+ on time)

Ranked by chance you reach Boston on time. Total trip = scheduled departure to arrival, layover included. Layovers up to 4 hours. Pick a connection for the details.


United Details →	SJU 07:20 → IAD 11:21UA 2022	1h 34m Dulles	IAD 12:55 → BOS 14:40UA 1392	7h 20m	99%	79%
United Details →	SJU 01:00 → EWR 05:10UA 2219	1h 50m Newark	EWR 07:00 → BOS 08:17UA 593	7h 17m	92%	78%
JetBlue Details →	SJU 06:00 → TPA 08:59B6 452	50m Tampa	TPA 09:49 → BOS 12:51B6 892	6h 51m	94%	75%
Southwest Details →	SJU 05:20 → BWI 09:30WN 3717	1h 10m Baltimore	BWI 10:40 → BOS 12:10WN 887	6h 50m	93%	74%
American Details →	SJU 07:00 → PHL 11:04AA 3063	1h 46m Philadelphia	PHL 12:50 → BOS 14:23AA 2882	7h 23m	96%	73%
United Details →	SJU 16:55 → IAD 20:56UA 2024	1h 14m Dulles	IAD 22:10 → BOS 23:59UA 755	7h 04m	91%	72%
JetBlue Details →	SJU 05:01 → JFK 08:54B6 2904	1h 06m New York	JFK 10:00 → BOS 11:33B6 1018	6h 31m	87%	68%
JetBlue Details →	SJU 12:04 → JFK 15:59B6 1104	1h 16m New York	JFK 17:15 → BOS 18:49B6 818	6h 45m	82%	52%
Tight connection: often missed
JetBlue Details →	SJU 12:46 → TPA 15:49B6 2152	56m Tampa	TPA 16:45 → BOS 19:55B6 592	7h 08m	66%	38%
JetBlue Details →	SJU 11:09 → FLL 13:50B6 54	47m Fort Lauderdale	FLL 14:37 → BOS 17:56B6 70	6h 47m	63%	35%
American Details →	SJU 16:38 → MIA 19:34AA 2581	46m Miami	MIA 20:20 → BOS 23:41AA 2539	7h 03m	51%	29%

Same layover, different day-part

How often the first flight arrives too late to connect (45 min minimum), for one-ticket layovers of 45–80 minutes.

Morning

TPA · 50m · leaves 06:00 6%

BWI · 1h 10m · leaves 05:20 7%

JFK · 1h 06m · leaves 05:01 13%

Afternoon and evening

PHL · 1h 02m · leaves 14:25 20%

TPA · 56m · leaves 12:46 34%

MIA · 46m · leaves 16:38 49%

Delays build through the day, so an afternoon first leg eats the layover. A short connection is fine early in the morning and a gamble later on.

Mixing airlines

One ticketMiss it and the airline rebooks you; bags go through. 45 min is enough.

Separate ticketsMiss it and you buy a new ticket. Re-check bags, clear security again: we require 90 min.


JetBlue B6 1048 SJU 07:00 → PHL American AA 2882 PHL 12:50 → BOS Connection details →	1h 49m	7h 23m	94%	72%
JetBlue B6 2890 SJU 06:00 → EWR United UA 1669 EWR 11:59 → BOS Connection details →	2h 00m	7h 16m	90%	72%
JetBlue B6 1104 SJU 12:04 → JFK Delta DL 5798 JFK 17:30 → BOS Connection details →	1h 31m	7h 10m	66%	39%

Rank all connections, any airlines →

Regional partners count as the airline that sells them: SkyWest flying Delta Connection is one Delta ticket.

How these are worked out. Makes the connection: share of the last year’s flights where the first flight arrived with at least 45 minutes to spare (90 on separate tickets). Arrives on time: first flight not cancelled × connection made × second flight not cancelled and arriving within 15 minutes. Not yet counted: the second flight also leaving late (which helps), gate-to-gate distance at the hub, and rebooking after a missed connection.

About this data: US DOT on-time records, Aug 2025 – Jul 2026, all US airlines; regional flights count under the airline that sells them. Schedules (which flights and connections exist, and their times) are as of Jun 6 – Jul 31, 2026; seasonal flights outside that window aren’t ranked. Rebuilt monthly. JSON