Flight number record
DL 3123
Delta Air Lines · Salt Lake City to San Antonio
- Route
- SLC → SAT
- Departs
- 09:50
- Flights
- 250
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 3123, check with Delta Air Lines.
DL 3123 lands a B+, 7 points better than the national rate of 77.3%. About one flight in six arrives 15 minutes late or worse, and those flights are late by roughly 40 minutes on average. That rests on 250 flights, with a median arrival 7 minutes early.
Set against the rest of the country, DL 3123's record is 7 points better than the US average of 77.3%. That gap is worth roughly 66 fewer late arrivals for every thousand flights.
Key figures
On time
83.9%
Arrivals under 15 minutes late, of 248 completed flights
Avg delay
41 min
Across delayed arrivals only, not all flights
Cancelled
0.80%
National rate is 1.89%
1 hour+ late
3.2%
National rate is 8.3%
These figures cover 250 flights between September 2025 and August 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.
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Schedule
When DL 3123 flies
DL 3123 flies SLC to SAT without a single fixed slot. Its most common scheduled departure was 09:50, used on 102 of 250 flights, with 09:55 (75 flights) and 09:45 (37 flights) next.
- Departs 09:50102 flights40.8%
- Departs 09:5575 flights30.0%
- Departs 09:4537 flights14.8%
Scale runs 0% to 100%.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 09:50 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 83.9%, and DL 3123 runs level with that at 83.9%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
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Against the route
DL 3123 next to SLC to SAT
Every carrier on SLC to SAT combined arrived on time 84.5% of the time across 1,013 flights, so DL 3123 is about level with it. Across its whole network Delta Air Lines managed 81.1%, which this flight beats by 3 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 3123thin sample | 250 | 83.9% | 41 min | 0.80% | B+ |
| All Delta Air Lines on SLC–SAT | 1,013 | 84.5% | 62 min | 0.79% | B+ |
| All carriers on SLC–SAT | 1,013 | 84.5% | 62 min | 0.79% | B+ |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 3123 quarter by quarter
Quarter by quarter DL 3123 held fairly steady: 82.6% in Jan–Mar 2026, 81.8% in Apr–Jun 2026 and 87.1% in Jul–Sep 2026. A spread of 5 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.
- Oct–Dec 202512 flights—
- Jan–Mar 202687 flights82.6%
- Apr–Jun 202689 flights81.8%
- Jul–Sep 202662 flights87.1%
Scale runs 75% to 95%. Rows with fewer than 30 flights show a dash.
By weekday, DL 3123 did best on Monday at 94.4% on time and worst on Sunday at 77.8%. Each day rests on about 36 flights, so a gap of 17 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 3123 runs when it is late
Most of the lateness is short. 26 of the 40 late arrivals were under half an hour behind, and 8 reached an hour or more.
- 15+ min early61 flights24.6%
- Within 15 min147 flights59.3%
- 15–29 min late26 flights10.5%
- 30–59 min late6 flights2.4%
- 1–2 hours late5 flights2.0%
- 2+ hours late3 flights1.2%
Scale runs 0% to 100%.
Share of 248 completed flights by arrival against schedule.
8 of 37 late departures made up the time and arrived on time, 22% of them. 11 flights left on time and still arrived late.
The worst days
Worst days for DL 3123
The latest arrival of the period was on 29 January 2026, 3 hours 2 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on five of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 29 January 2026 | 3 hours 2 minutes | Carrier |
| 18 March 2026 | 2 hours 55 minutes | Carrier |
| 1 May 2026 | 2 hours 9 minutes | Carrier |
| 4 May 2026 | 1 hour 27 minutes | Carrier |
| 8 March 2026 | 1 hour 21 minutes | Carrier |
Delay causes
Why DL 3123 runs late
Carrier accounts for 74% of the 1,643 delay minutes carriers reported here, and the remaining four split what is left.
- 74%Carrier
- 17%National Airspace System
- 9%Late-arriving aircraft
The largest share of delay minutes, 74%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 1,218 of the 1,643 delay minutes reported here. The split is drawn from 1,643 delay minutes reported on DL 3123.
Cancellations are rare at 0.80%, below the national 1.89% 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 routes
What a delay on this flight costs
Badly late arrivals are rare here: only 3.2% land an hour or more behind schedule, against 8.3% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
The 1,087 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.
Every one of the 250 flights under DL 3123 in the data flew SLC to SAT. The number was not reused on any other city pair, which makes this a clean record of one route.
One caution: this is a thin sample. 250 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 DL 3123
For a booking, read DL 3123 as 83.9% on time with 0.80% cancelled over 250 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- SLC to SAT, every carrier and departure
- SAT to SLC, the return direction
- Delta Air Lines 2797 on the same route83.6%
- Salt Lake City International (SLC) delay statistics
- San Antonio International (SAT) delay statistics
- Delta Air Lines on-time record
- Every Delta Air Lines flight number with a record
- The most and least reliable flight numbers in the US
- The best day of the week to fly, and why it is the second lever
A flight number here means Delta Air Lines’s own number as it reports to the DOT. How the figures are computed is on the methodology page.
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.