Carrier route record

F9SFO→SAN

Frontier Airlines · San Francisco to San Diego

Flights: 196
Period: July 2025 to June 2026
Share of route: 3%
Carriers: 5

Historical statistics for July 2025 to June 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 53.7% of flights arrive inside the 15-minute window, 24 points worse than the national rate of 77.6%. Late arrivals average a little over an hour. Treat any tight connection here as a coin flip. That rests on 196 flights. The strongest carrier on the route with a full sample, United Airlines, flew 2,598 at 76.2% on time.

United Airlines is the most reliable of the three carriers covered here at 76.2% on time across 2,598 flights.

On time

53.7%

Arrivals under 15 minutes late, of 190 completed flights

Avg delay

76 min

Across delayed arrivals only, not all flights

Cancelled

3.06%

National rate is 1.81%

Whole route

66.6%

Every carrier on SFO to SAN, 6,548 flights

These figures cover 196 flights between July 2025 and June 2026. Beyond the headline rate, 17.9% 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 SFO to SAN

Frontier flew 196 of the 6,548 flights on SFO to SAN, about 3% of it. Its 53.7% on time is 13 points worse than the route as a whole, which runs 66.6%. Ranked by on-time rate it is number four of five carriers on the route, where the range runs from Alaska at 88.8% to Southwest at 52.8%. 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 76.2% of the time; Southwest Airlines manages 52.8%. Sample sizes sit next to every figure, because a two-point gap across 1,935 flights means less than a ten-point one.

On-time performance by carrier on SFO to SAN
Airline	Flights	On time	Avg delay	Cancelled	Grade
Alaska Airlinesthin sample	304	88.8%	49 min	0.33%	A+
United Airlines	2,598	76.2%	55 min	0.46%	B+
SkyWest Airlines	1,515	64.8%	57 min	2.05%	D
Frontier Airlines (this page)thin sample	196	53.7%	76 min	3.06%	F−
Southwest Airlines	1,935	52.8%	62 min	1.24%	F

The spread between United and Southwest is 23 points, wide enough that it should decide the booking. On a hundred trips that is 23 more arrivals inside the on-time window.

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 22 points, against 23 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am—
8am–11am68 flights57.4%
11am–2pm10 flights—
2pm–5pm52 flights61.5%
5pm–8pm5 flights—
8pm–5am61 flights40.0%

Scale runs 30% to 65%. Rows with fewer than 30 flights show a dash.

The 8pm–5am window is where this operation falls apart: 40.0% on time, against 61.5% for the 2pm–5pm 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 8am–11am window is the busiest, with 68 flights scheduled in it.

Across the year

Frontier on SFO to SAN through the year

Jul–Sep 202554 flights48.1%
Oct–Dec 202565 flights69.2%
Jan–Mar 20269 flights—
Apr–Jun 202668 flights41.9%

Scale runs 35% 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 53.7% on time across 196 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 Apr–Jun 2026 at 41.9%, a swing of 27 points on roughly 65 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 78.1% on time and Monday the weakest at 45.7%. 32 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 60% of the 6,667 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.

Late-arriving aircraft
60%
National Airspace System
25%
Carrier
15%

60% 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 6,667 reported delay minutes here, that single category outweighs weather by 60 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 6,667 reported delay minutes.

Cancellations run at 3.06%, against 1.81% nationally. That is roughly 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. 17.9% 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 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 2pm–5pm window matters as much as it does.

The return leg is a different operation and performs like one: it runs 47.0% on time across 196 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.

One caution: this is a thin sample. 196 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 3.06% cancellation rate. A late arrival costs you a little over an hour; a cancelled flight costs you the day. Book the 2pm–5pm departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 190 completed flights over 12 months sit behind that.

Where to go next

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.

Key figures