Carrier route record
F9SJU→PHL
Frontier Airlines · San Juan to Philadelphia
- Flights
- 867
- 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 SJU to PHL carries a cancellation problem, not just a delay problem: 3.3% 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 867 flights, with a median arrival 4 minutes late.
The national on-time rate over the same period is 77.6%, so Frontier on SJU to PHL runs 17 points behind the country as a whole. Across a thousand flights that is about 166 extra late arrivals.
Key figures
On time
61.0%
Arrivals under 15 minutes late, of 835 completed flights
Avg delay
83 min
Across delayed arrivals only, not all flights
Cancelled
3.34%
National rate is 1.81%
Whole route
70.5%
Every carrier on SJU to PHL, 1,881 flights
These figures cover 867 flights between July 2025 and June 2026. Beyond the headline rate, 13.9% 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 SJU to PHL
Frontier flew 867 of the 1,881 flights on SJU to PHL, about 46% of it. Its 61.0% on time is 10 points worse than the route as a whole, which runs 70.5%. Ranked by on-time rate it is last of four carriers on the route, where the range runs from JetBlue at 95.8% to Frontier at 61.0%. 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 | 95.8% | 25 min | 0.00% | A+ |
| American Airlines | 701 | 79.4% | 95 min | 2.71% | B |
| Spirit Airlinesthin sample | 216 | 67.5% | 67 min | 7.41% | C− |
| Frontier Airlines (this page) | 867 | 61.0% | 83 min | 3.34% | D− |
Flight by flight
Frontier flight numbers on SJU to PHL
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 34 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–8am92 flights85.1%
- 8am–11am15 flights—
- 11am–2pm240 flights57.5%
- 2pm–5pm106 flights64.8%
- 5pm–8pm73 flights80.8%
- 8pm–5am341 flights50.9%
Scale runs 40% to 90%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 50.9% on time, against 85.1% for the 5am–8am 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 341 flights scheduled in it.
Across the year
Frontier on SJU to PHL through the year
July is the worst month at 38.5% on time, 45 points below May, the best at 83.1%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. June was the busiest month here, with 90 flights.
Across the week, Wednesday is the strongest day at 67.0% on time and Monday the weakest at 55.8%. 11 points is a smaller lever than departure hour, but it is free.
Delay causes
Why Frontier runs late on this route
One category carries most of the weight here. Late-arriving aircraft accounts for 48% of the 27,000 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.
- 48%Late-arriving aircraft
- 40%Carrier
- 11%National Airspace System
48% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 27,000 reported delay minutes here, that single category outweighs weather by 48 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 27,061 reported delay minutes.
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 11,000 of the 27,000 delay minutes reported here.
Cancellations run at 3.34%, 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. 13.9% 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 57.9% on time across 865 flights, 3 points below 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. 867 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 SJU to PHL
Put together: the delay figures matter less here than the 3.34% cancellation rate. A late arrival costs you an hour and a half; a cancelled flight costs you the day. Book the 5am–8am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 835 completed flights over 12 months sit behind that.
Related
Where to go next
- SJU to PHL, every carrier
- Frontier on PHL to SJU, the return leg
- American Airlines on SJU to PHL79.4%
- Spirit Airlines on SJU to PHL67.5%
- Frontier Airlines network-wide record
- Luis Munoz Marin International (SJU) delay statistics
- Philadelphia International (PHL) delay statistics
- The US routes with the most cancellations
- Why the first flight of the morning is statistically safest
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.