Carrier route record
WNLAS→SAT
Southwest Airlines · Las Vegas to San Antonio
- Flights
- 1,564
- Period
- July 2025 to June 2026
- Share of route
- 76%
- Carriers
- 3
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on LAS to SAT sits in the middle of the pack with a C+. Close to three flights in four arrive on time by the DOT's definition, 4 points worse than the national rate of 77.6%. The late ones land about 50 minutes behind schedule. That rests on 1,564 flights, with a median arrival 1 minute late.
The national on-time rate over the same period is 77.6%, so Southwest on LAS to SAT runs 4 points behind the country as a whole. Across a thousand flights that is about 43 extra late arrivals.
Key figures
On time
73.3%
Arrivals under 15 minutes late, of 1,556 completed flights
Avg delay
50 min
Across delayed arrivals only, not all flights
Cancelled
0.19%
National rate is 1.81%
Whole route
75.8%
Every carrier on LAS to SAT, 2,053 flights
These figures cover 1,564 flights between July 2025 and June 2026. On-time means an arrival less than 15 minutes after the scheduled gate time, the same threshold the Department of Transportation uses in its own reports. Cancelled and diverted flights are excluded from the on-time rate and counted separately, which is why the cancellation column matters on its own.
Carrier by carrier
Southwest against every carrier on LAS to SAT
Southwest flew 1,564 of the 2,053 flights on LAS to SAT, most of the route. Its 73.3% on time is 3 points worse than the route as a whole, which runs 75.8%. Ranked by on-time rate it is last of three carriers on the route, where the range runs from Frontier at 85.1% to Southwest at 73.3%. 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 |
|---|---|---|---|---|---|
| Frontier Airlinesthin sample | 277 | 85.1% | 62 min | 0.72% | A+ |
| Spirit Airlinesthin sample | 212 | 82.5% | 94 min | 0.47% | B+ |
| Southwest Airlines (this page) | 1,564 | 73.3% | 50 min | 0.19% | C+ |
Departure window
When Southwest runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 39 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–8am302 flights95.7%
- 8am–11am276 flights80.1%
- 11am–2pm257 flights77.4%
- 2pm–5pm256 flights60.4%
- 5pm–8pm343 flights60.6%
- 8pm–5am130 flights56.7%
Scale runs 50% to 100%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 56.7% on time, against 95.7% 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 5pm–8pm window is the busiest, with 343 flights scheduled in it.
Across the year
Southwest on LAS to SAT through the year
Delays peak in May, when the on-time rate falls to 61.1%. February is the strongest month at 83.6%. Moving a flexible trip across that boundary buys 22 points. December was the busiest month here, with 150 flights.
Across the week, Saturday is the strongest day at 84.2% on time and Thursday the weakest at 66.7%. 18 points is a smaller lever than departure hour, but it is free.
Delay causes
Why Southwest runs late on this route
One category carries most of the weight here. Late-arriving aircraft accounts for 58% of the 21,000 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.
- 58%Late-arriving aircraft
- 32%Carrier
- 10%National Airspace System
- 0%Security
58% 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 21,000 reported delay minutes here, that single category outweighs weather by 58 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 20,834 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 95.7% on time here.
Cancellations are rare at 0.19%, below the national 1.81% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here costs
6.8% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about 50 minutes, which a normal layover absorbs.
The 1,069 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
The return leg is a different operation and performs like one: it runs 81.6% on time across 1,571 flights, 8 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 8 points of difference.
The sample behind these figures is 1,564 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.
What to do with this
Booking Southwest on LAS to SAT
Put together: the calendar is the biggest lever here, not the carrier or the hour. February runs 83.6% on time and May 61.1%, a swing of 22 points. If the dates move at all, move them out of May before you think about anything else. 1,556 completed flights over 12 months sit behind that.
Related
Where to go next
- LAS to SAT, every carrier
- Southwest on SAT to LAS, the return leg
- Frontier Airlines on LAS to SAT85.1%
- Spirit Airlines on LAS to SAT82.5%
- Southwest Airlines network-wide record
- Harry Reid International (LAS) delay statistics
- San Antonio International (SAT) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
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.