Carrier route record
F9SFO→SAN
Frontier Airlines · San Francisco to San Diego
- Flights
- 214
- Period
- September 2025 to August 2026
- Share of route
- 3%
- Carriers
- 5
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with Frontier Airlines.
Frontier on SFO to SAN earns an F−, which is as low as this site's scale goes for a reason. Only 48.3% of flights arrive inside the 15-minute window, 29 points worse than the national rate of 77.3%. Late arrivals average an hour and a half. Treat any tight connection here as a coin flip. That rests on 214 flights. The strongest carrier on the route with a full sample, United Airlines, flew 2,666 at 72.8% on time.
United Airlines is the most reliable of the three carriers covered here at 72.8% on time across 2,666 flights.
Key figures
On time
48.3%
Arrivals under 15 minutes late, of 205 completed flights
Avg delay
95 min
Across delayed arrivals only, not all flights
Cancelled
4.21%
National rate is 1.89%
Whole route
62.2%
Every carrier on SFO to SAN, 6,723 flights
These figures cover 214 flights between September 2025 and August 2026. Beyond the headline rate, 25.4% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
Frontier against every carrier on SFO to SAN
Frontier flew 214 of the 6,723 flights on SFO to SAN, about 3% of it. Its 48.3% on time is 14 points worse than the route as a whole, which runs 62.2%. Ranked by on-time rate it is number four of five carriers on the route, where the range runs from Alaska at 82.9% to Southwest at 47.9%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
The choice of carrier is not cosmetic here. United Airlines arrives on time 72.8% of the time; Southwest Airlines manages 47.9%. Sample sizes sit next to every figure, because a two-point gap across 2,070 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Alaska Airlinesthin sample | 331 | 82.9% | 44 min | 1.21% | B |
| United Airlines | 2,666 | 72.8% | 54 min | 0.34% | C+ |
| SkyWest Airlines | 1,442 | 60.1% | 59 min | 2.36% | D |
| Frontier Airlines (this page)thin sample | 214 | 48.3% | 95 min | 4.21% | F− |
| Southwest Airlines | 2,070 | 47.9% | 62 min | 1.35% | F |
The spread between United and Southwest is 25 points, wide enough that it should decide the booking. On a hundred trips that is 25 more arrivals inside the on-time window.
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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 51 points, against 25 points between the best and worst carrier.
- 5am–8am—
- 8am–11am33 flights81.8%
- 11am–2pm17 flights—
- 2pm–5pm52 flights61.5%
- 5pm–8pm5 flights—
- 8pm–5am107 flights31.3%
Scale runs 25% to 85%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 31.3% on time, against 81.8% for the 8am–11am 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 107 flights scheduled in it.
Across the year
Frontier on SFO to SAN through the year
- Jul–Sep 202510 flights—
- Oct–Dec 202565 flights69.2%
- Jan–Mar 20269 flights—
- Apr–Jun 202668 flights41.9%
- Jul–Sep 202662 flights25.4%
Scale runs 15% to 75%. Rows with fewer than 30 flights show a dash.
Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 48.3% on time across 214 flights.
Frontier on SFO to SAN did not run the same all year. Its best quarter was Oct–Dec 2025 at 69.2% on time and its weakest Jul–Sep 2026 at 25.4%, a swing of 44 points on roughly 71 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.
Across the week, Saturday is the strongest day at 71.9% on time and Thursday the weakest at 40.6%, a spread of 31 points.
Arrival by arrival
How late Frontier on SFO to SAN runs when it is late
The 106 late arrivals split 23 under half an hour, 31 between 30 and 60 minutes, and 52 an hour or more.
- 15+ min early29 flights14.1%
- Within 15 min70 flights34.1%
- 15–29 min late23 flights11.2%
- 30–59 min late31 flights15.1%
- 1–2 hours late32 flights15.6%
- 2+ hours late20 flights9.8%
Scale runs 0% to 100%.
Share of 205 completed flights by arrival against schedule.
Time lost at the gate mostly stays lost. Of 110 departures that left 15 minutes late or more, only 12 made it up before arrival. 8 flights left on time and still arrived late.
The worst days
Worst days for Frontier on SFO to SAN
The latest arrival of the period was on 5 June 2026, 12 hours 49 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). On four of the five worst days the largest share was filed as national airspace system delay.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 5 June 2026 | 12 hours 49 minutes | Carrier |
| 16 August 2026 | 11 hours 52 minutes | National Airspace System |
| 9 August 2026 | 10 hours 53 minutes | National Airspace System |
| 13 June 2026 | 10 hours 7 minutes | National Airspace System |
| 19 July 2026 | 9 hours 58 minutes | National Airspace System |
Delay causes
Why Frontier runs late on this route
Late-arriving aircraft accounts for 55% of the 10,000 delay minutes carriers reported here, and the remaining four split what is left.
- 55%Late-arriving aircraft
- 34%National Airspace System
- 11%Carrier
55% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 10,000 reported delay minutes here, that single category outweighs weather by 55 to one. The split is drawn from 10,093 reported delay minutes.
34% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 3,447 minutes out of 10,000, against a national NAS share of 21%.
Cancellations run at 4.21%, against 1.89% nationally. That is about one flight in 25 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
25.4% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.
At 447 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 8am–11am window matters as much as it does.
The return leg is a different operation and performs like one: it runs 37.9% on time across 214 flights, 10 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 10 points of difference.
One caution: this is a thin sample. 214 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 SFO to SAN
Put together: the delay figures matter less here than the 4.21% cancellation rate. A late arrival costs you an hour and a half; a cancelled flight costs you the day. Book the 8am–11am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 205 completed flights over 12 months sit behind that.
Related
Where to go next
- SFO to SAN, every carrier
- Frontier on SAN to SFO, the return leg
- Alaska Airlines on SFO to SAN82.9%
- United Airlines on SFO to SAN72.8%
- SkyWest Airlines on SFO to SAN60.1%
- Southwest Airlines on SFO to SAN47.9%
- Frontier Airlines network-wide record
- San Francisco International (SFO) delay statistics
- San Diego International (SAN) delay statistics
- The US routes with the most cancellations
- Same route, different airline: where the carrier you pick matters most
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.