Route reliability record
SJU→PHL
San Juan to Philadelphia
- Flights
- 1,881
- Period
- July 2025 to June 2026
- Distance
- 1,576 mi
- Carriers
- 4
This route 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, about seven flights in ten arrive on time, worth a C− overall. The punctuality figure counts only flights that actually departed, so it flatters an operation that cancels this often. That rests on 1,881 SJU to PHL flights, of which American Airlines flew 701 at 79.4% on time.
Best time to fly SJU to PHL: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 87.5% of the time and Wednesday flights 77.4%, against 70.5% for the route overall.
The national on-time rate over the same period is 77.6%, so this route runs 7 points behind the country as a whole. Across a thousand flights that is about 71 extra late arrivals.
Key figures
On time
70.5%
Arrivals under 15 minutes late, of 1,811 completed flights
Avg delay
84 min
Across delayed arrivals only, not all flights
Cancelled
3.40%
National rate is 1.81%
Best carrier
American
79.4% on time across 701 flights
These figures cover 1,881 flights between July 2025 and June 2026. Beyond the headline rate, 9.9% 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
Which airline is most reliable on SJU to PHL
The choice of carrier is not cosmetic here. American Airlines arrives on time 79.4% of the time; Frontier Airlines manages 61.0%. Sample sizes sit next to every figure, because a two-point gap across 867 flights means less than a ten-point one.
| 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 | 867 | 61.0% | 83 min | 3.34% | D− |
Frontier Airlines cancels 3.3% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.
Flight by flight
Flights on SJU to PHL
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
Best ways to make this trip
The most reliable ways to fly San Juan to Philadelphia
Every airline on this route, ranked by how often a scheduled flight actually operated and arrived on time, with its best departure time and most punctual flight number. No nearby airport pair beat these.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. SJU → PHLSan Juan to Philadelphia | American Airlines | 77.2% | 79.4% | 2.71% | 5am–8am, Wed | — |
| 2. SJU → PHLSan Juan to Philadelphia | Frontier Airlines | 59.0% | 61.0% | 3.34% | 5am–8am, Wed | F9 1015 01:59 |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 36 points, against 18 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am440 flights87.5%
- 8am–11am115 flights79.8%
- 11am–2pm411 flights68.1%
- 2pm–5pm298 flights71.8%
- 5pm–8pm136 flights75.8%
- 8pm–5am481 flights51.5%
Scale runs 45% to 95%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 51.5% on time, against 87.5% 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 481 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 30 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
December is the weak month at 56.3% on time, against 85.8% in June. 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. April was the busiest month here, with 224 flights.
Across the week, Wednesday is the strongest day at 77.4% on time and Sunday the weakest at 66.5%. 11 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
One category carries most of the weight here. Late-arriving aircraft accounts for 44% of the 45,000 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.
- 44%Late-arriving aircraft
- 44%Carrier
- 12%National Airspace System
- 0%Extreme weather
44% 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 45,000 reported delay minutes here, that single category outweighs weather by 44 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 44,821 reported delay minutes.
The largest share of delay minutes, 44%, 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 20,000 of the 45,000 delay minutes reported here.
Cancellations run at 3.40%, 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 actually costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 9.9% 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 63.1% on time across 1,879 flights, 7 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 7 points of difference.
The sample behind these figures is 1,881 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
Work out the risk of missing a connection in PHL after this flight
What to do with this
Booking this route
Put together: the delay figures matter less here than the 3.40% 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. 1,811 completed flights over 12 months sit behind that.
Common questions
SJU to PHL questions
How often is SJU to PHL delayed?
Roughly one flight in three arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 29.5% of the 1,881 flights in this analysis, against 22.4% nationally. Delayed flights are late by an hour and a half on average.
Which airline is most reliable on SJU to PHL?
American Airlines leads at 79.4% on time across 701 flights. Frontier Airlines is at the other end on 61.0%, a gap of 18 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on SJU to PHL?
The 5am–8am departure window is the strongest at 87.5% on time. The 8pm–5am window is the weakest at 51.5%, 36 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are December delays on SJU to PHL?
December is the weakest month at 56.3% on time, compared with 85.8% in June. Across the year that is 30 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- PHL to SJU — the return legseparate record
- Luis Munoz Marin International (SJU) delay statistics
- Philadelphia International (PHL) delay statistics
- American Airlines on SJU to PHL79.4%
- Spirit Airlines on SJU to PHL67.5%
- Frontier Airlines on SJU to PHL61.0%
- SJU to MCO, a related route78.9%
- ATL to PHL, a related route74.9%
- SJU to JFK, a related route79.3%
- JetBlue Airways on-time record95.8%
- American Airlines on-time record79.4%
- Spirit Airlines on-time record67.5%
- The US routes with the most cancellations
- Same route, different airline: where the carrier you pick matters most
Direction matters. SJU to PHL and PHL to SJU are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.