Carrier route record
UASAT→DEN
United Airlines · San Antonio to Denver
- Flights
- 1,207
- Period
- July 2025 to June 2026
- Share of route
- 40%
- Carriers
- 4
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with United Airlines.
United on SAT to DEN lands a B+, 4 points better than the national rate of 77.6%. Roughly one flight in five arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That is a workable record, not a spotless one. That rests on 1,207 flights. The strongest carrier on the route with a full sample, Southwest Airlines, flew 1,432 at 80.8% on time.
Set against the rest of the country, United's SAT to DEN record is 4 points better than the US average of 77.6%. That gap is worth roughly 40 fewer late arrivals for every thousand flights.
Key figures
On time
81.6%
Arrivals under 15 minutes late, of 1,195 completed flights
Avg delay
78 min
Across delayed arrivals only, not all flights
Cancelled
0.58%
National rate is 1.81%
Whole route
81.0%
Every carrier on SAT to DEN, 3,027 flights
These figures cover 1,207 flights between July 2025 and June 2026. The median arrival is 7 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
Carrier by carrier
United against every carrier on SAT to DEN
United flew 1,207 of the 3,027 flights on SAT to DEN, about 40% of it. Its 81.6% on time is about level with the route as a whole at 81.0%. Ranked by on-time rate it is number two of four carriers on the route, where the range runs from SkyWest at 88.9% to Frontier at 79.6%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
The two carriers here are closely matched: about a point separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlinesthin sample | 18 | 88.9% | 169 min | 0.00% | A+ |
| United Airlines (this page) | 1,207 | 81.6% | 78 min | 0.58% | B+ |
| Southwest Airlines | 1,432 | 80.8% | 53 min | 0.28% | B+ |
| Frontier Airlines | 370 | 79.6% | 90 min | 0.54% | B+ |
No carrier stands out. Southwest tops the table at 80.8%, about a point clear of the bottom, which is inside the range this kind of sample moves year to year.
Flight by flight
United flight numbers on SAT to DEN
Departure window
When United runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 23 points, against about a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am100 flights93.9%
- 8am–11am365 flights84.1%
- 11am–2pm378 flights85.1%
- 2pm–5pm345 flights71.1%
- 5pm–8pm19 flights—
- 8pm–5am—
Scale runs 65% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 93.9% of the time, against 71.1% for the afternoon window. That is 23 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 11am–2pm window is the busiest, with 378 flights scheduled in it.
Across the year
United on SAT to DEN through the year
July is the worst month at 72.4% on time, 16 points below February, the best at 88.0%. 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. July was the busiest month here, with 124 flights.
The day of the week is close to irrelevant here: 4 points separates the best day from the worst. Weekly demand peaks are not what drives the delays on this operation.
Delay causes
Why United runs late on this route
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 17,000 reported delay minutes.
- 37%Carrier
- 36%National Airspace System
- 25%Late-arriving aircraft
- 1%Extreme weather
36% 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 6,241 minutes out of 17,000, against a national NAS share of 21%. The split is drawn from 17,206 reported delay minutes.
The largest share of delay minutes, 37%, 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 6,378 of the 17,000 delay minutes reported here.
Cancellations are rare at 0.58%, 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
7.9% 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 a little over an hour, which a normal layover absorbs.
The 794 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 runs 81.9% on time across 1,205 flights, within half a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
The sample behind these figures is 1,207 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 United on SAT to DEN
Put together: the calendar is the biggest lever here, not the carrier or the hour. February runs 88.0% on time and July 72.4%, a swing of 16 points. If the dates move at all, move them out of July before you think about anything else. 1,195 completed flights over 12 months sit behind that.
Related
Where to go next
- SAT to DEN, every carrier
- United on DEN to SAT, the return leg
- Southwest Airlines on SAT to DEN80.8%
- Frontier Airlines on SAT to DEN79.6%
- United Airlines network-wide record
- San Antonio International (SAT) delay statistics
- Denver International (DEN) delay statistics
- The best time of day to fly, according to 7.04 million flight records
- Worst months to fly in the US, ranked by the data
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.