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

Connect in the morning. The same 75-minute layover misses 2% of the time at 7 am and 31% of the time at 9 pm.

Nonstops


Delta	BOS	SJU	4h 04m	76%	1.5%	398	Flying now
JetBlue	BOS	SJU	4h 02m	68%	2.8%	1,192	Flying now
Spirit	BOS	SJU	4h 07m	54%	8.2%	146	Not flying now
Frontier	BOS	SJU	3h 59m	45%few flights	2.9%	34	Not flying now

Best connections, one ticket

Most reliable Quickest (80%+ on time)

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


American Details →	BOS 05:10 → MIA 08:38AA 1418	2h 39m Miami	MIA 11:17 → SJU 14:12AA 2584	9h 02m	100%	92%
American Details →	BOS 06:05 → CLT 08:30AA 418	2h 33m Charlotte	CLT 11:03 → SJU 14:50AA 783	8h 45m	98%	83%
United Details →	BOS 05:45 → IAD 07:23UA 1734	1h 11m Dulles	IAD 08:34 → SJU 12:34UA 2021	6h 49m	98%	80%
American Details →	BOS 06:00 → MIA 09:30AA 873	3h 33m Miami	MIA 13:03 → SJU 15:47AA 2581	9h 47m	98%	80%
Delta Details →	BOS 09:05 → JFK 10:24DL 5720 · flown by Republic	2h 06m New York	JFK 12:30 → SJU 16:29DL 1961	7h 24m	98%	80%
Delta Details →	BOS 06:50 → ATL 09:33DL 695	3h 33m Atlanta	ATL 13:06 → SJU 16:46DL 1946	9h 56m	99%	79%
JetBlue Details →	BOS 12:30 → FLL 15:56B6 269	3h 19m Fort Lauderdale	FLL 19:15 → SJU 21:53B6 553	9h 27m	97%	78%
American Details →	BOS 06:00 → PHL 07:37AA 1146	1h 51m Philadelphia	PHL 09:28 → SJU 13:33AA 903	7h 33m	98%	77%
Tight connection: often missed
JetBlue Details →	BOS 17:29 → MCO 20:48B6 451	1h 22m Orlando	MCO 22:10 → SJU 01:40 +1B6 1433	7h 41m	69%	37%
JetBlue Details →	BOS 16:07 → JFK 17:25B6 317	1h 04m New York	JFK 18:29 → SJU 22:45B6 2903	6h 38m	61%	33%
Southwest Details →	BOS 17:20 → BWI 19:10WN 1898	1h 00m Baltimore	BWI 20:10 → SJU 00:40 +1WN 1104	6h 55m	52%	22%

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

IAH · 1h 13m · leaves 05:47 2%

IAD · 1h 11m · leaves 05:45 2%

ATL · 1h 17m · leaves 09:05 6%

Afternoon and evening

JFK · 1h 04m · leaves 16:07 39%

BWI · 1h 00m · leaves 17:20 48%

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.


Delta DL 1580 BOS 07:05 → MCO Southwest WN 1465 MCO 12:10 → SJU Connection details →	1h 55m	8h 00m	94%	79%
American AA 2735 BOS 09:00 → MCO Southwest WN 2703 MCO 15:25 → SJU Connection details →	3h 09m	9h 25m	97%	79%
Frontier F9 3085 BOS 06:00 → ATL Delta DL 1946 ATL 13:06 → SJU Connection details →	4h 00m	10h 46m	99%	77%

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