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 3 in 4 on time.

Nonstops (seasonal or thin)


United	IAD	SJU	4h 00m	79%	0.5%	632	Flying now
Frontier	IAD	SJU	3h 53m	51%	1.3%	75	Not flying now

Best connections, any airlines

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.


United Details →	IAD 17:59 → IAH 20:25UA 2217	3h 31m Houston	IAH 23:56 → SJU 05:29 +1UA 1497	11h 30m	98%	84%
United Details →	IAD 06:30 → DEN 08:22UA 2031	1h 21m Denver	DEN 09:43 → SJU 17:38UA 1339	11h 08m	100%	83%
American Details →	IAD 06:33 → CLT 08:00AA 1216	3h 03m Charlotte	CLT 11:03 → SJU 14:50AA 783	8h 17m	97%	81%
United + Deltatwo ticketsDetails →	IAD 08:15 → ATL 10:14UA 2739	2h 52m Atlanta	ATL 13:06 → SJU 16:46DL 1946	8h 31m	97%	79%
United Details →	IAD 10:31 → ORD 11:53UA 1252	2h 45m Chicago	ORD 14:38 → SJU 20:34UA 695	10h 03m	100%	79%
United Details →	IAD 06:30 → IAH 08:39UA 1935	1h 24m Houston	IAH 10:03 → SJU 15:42UA 1192	9h 12m	100%	79%
United + JetBluetwo ticketsDetails →	IAD 08:15 → STT 12:20UA 1443	3h 47m Charlotte Amalie	STT 16:07 → SJU 16:49B6 435	8h 34m	100%	77%
United + JetBluetwo ticketsDetails →	IAD 06:33 → EWR 07:52UA 2147	3h 26m Newark	EWR 11:18 → SJU 15:14B6 1889	8h 41m	100%	76%
Tight connection: often missed
American Details →	IAD 19:31 → DFW 21:50AA 1904	57m Dallas-Fort Worth	DFW 22:47 → SJU 04:39 +1AA 514	9h 08m	50%	24%

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

DTW · 55m · leaves 06:00 16%

Afternoon and evening

DFW · 57m · leaves 19:31 50%

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.

The table above includes two-ticket connections (marked “two tickets”), held to the 90-minute minimum. One ticket only →

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