Carrier route record
F9PHL→SJU
Frontier Airlines · Philadelphia to San Juan
- Flights
- 865
- Period
- July 2025 to June 2026
- Share of route
- 46%
- Carriers
- 4
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Frontier Airlines.
Frontier on PHL to SJU carries a cancellation problem, not just a delay problem: 3.4% of scheduled flights never operate, against 1.8% nationally. Of the ones that do fly, a little over half of flights arrive on time, worth a D− overall. The punctuality figure counts only flights that actually departed, so it flatters an operation that cancels this often. That rests on 865 flights, with a median arrival 7 minutes late.
The national on-time rate over the same period is 77.6%, so Frontier on PHL to SJU runs 20 points behind the country as a whole. Across a thousand flights that is about 197 extra late arrivals.
Key figures
On time
57.9%
Arrivals under 15 minutes late, of 834 completed flights
Avg delay
75 min
Across delayed arrivals only, not all flights
Cancelled
3.35%
National rate is 1.81%
Whole route
63.1%
Every carrier on PHL to SJU, 1,879 flights
These figures cover 865 flights between July 2025 and June 2026. Beyond the headline rate, 16.9% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.
Carrier by carrier
Frontier against every carrier on PHL to SJU
Frontier flew 865 of the 1,879 flights on PHL to SJU, about 46% of it. Its 57.9% on time is 5 points worse than the route as a whole, which runs 63.1%. Ranked by on-time rate it is last of four carriers on the route, where the range runs from JetBlue at 78.1% to Frontier at 57.9%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| JetBlue Airwaysthin sample | 97 | 78.1% | 138 min | 0.00% | B+ |
| American Airlines | 701 | 68.2% | 98 min | 2.00% | C |
| Spirit Airlinesthin sample | 216 | 59.8% | 69 min | 7.87% | D− |
| Frontier Airlines (this page) | 865 | 57.9% | 75 min | 3.35% | D− |
Flight by flight
Frontier flight numbers on PHL to SJU
Departure window
When Frontier runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 18 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am178 flights62.0%
- 8am–11am104 flights57.4%
- 11am–2pm107 flights64.8%
- 2pm–5pm95 flights47.3%
- 5pm–8pm79 flights46.7%
- 8pm–5am302 flights59.5%
Scale runs 40% to 70%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 46.7% on time, against 64.8% for the 11am–2pm slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 8pm–5am window is the busiest, with 302 flights scheduled in it.
Across the year
Frontier on PHL to SJU through the year
January is the weak month at 38.9% on time, against 72.6% in May. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. June was the busiest month here, with 90 flights.
Across the week, Tuesday is the strongest day at 66.7% on time and Sunday the weakest at 51.2%. 16 points is a smaller lever than departure hour, but it is free.
Delay causes
Why Frontier runs late on this route
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 26,000 reported delay minutes.
- 40%Carrier
- 27%Late-arriving aircraft
- 27%National Airspace System
- 6%Extreme weather
The largest share of delay minutes, 40%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 10,000 of the 26,000 delay minutes reported here. The split is drawn from 26,172 reported delay minutes.
Cancellations run at 3.35%, against 1.81% nationally. That is about one flight in 30 cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.
Connections and stage length
What a delay here costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 16.9% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.
At 1,576 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
The return leg is a different operation and performs like one: it runs 61.0% on time across 867 flights, 3 points above this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 3 points of difference.
One caution: this is a thin sample. 865 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking Frontier on PHL to SJU
Put together: the delay figures matter less here than the 3.35% cancellation rate. A late arrival costs you a little over an hour; a cancelled flight costs you the day. Book the 11am–2pm departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 834 completed flights over 12 months sit behind that.
Related
Where to go next
- PHL to SJU, every carrier
- Frontier on SJU to PHL, the return leg
- American Airlines on PHL to SJU68.2%
- Spirit Airlines on PHL to SJU59.8%
- Frontier Airlines network-wide record
- Philadelphia International (PHL) delay statistics
- Luis Munoz Marin International (SJU) delay statistics
- The US routes with the most cancellations
- What a cancellation rate actually tells you (and what it hides)
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.