Carrier route record
DLKOA→SEA
Delta Air Lines · Kailua-Kona to Seattle
- Flights
- 365
- Period
- September 2025 to August 2026
- Share of route
- 26%
- Carriers
- 2
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with Delta Air Lines.
Delta on KOA to SEA earns an A−. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 12 points better than the national rate of 77.3%. When something does go wrong the average delay runs roughly 45 minutes. That rests on 365 flights, with a median arrival 16 minutes early.
Set against the rest of the country, Delta's KOA to SEA record is 12 points better than the US average of 77.3%. That gap is worth roughly 122 fewer late arrivals for every thousand flights.
Key figures
On time
89.5%
Arrivals under 15 minutes late, of 352 completed flights
Avg delay
47 min
Across delayed arrivals only, not all flights
Cancelled
3.29%
National rate is 1.89%
Whole route
86.7%
Every carrier on KOA to SEA, 1,412 flights
These figures cover 365 flights between September 2025 and August 2026. The median arrival is 16 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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Carrier by carrier
Delta against every carrier on KOA to SEA
Delta flew 365 of the 1,412 flights on KOA to SEA, about 26% of it. Its 89.5% on time is 3 points better than the route as a whole, which runs 86.7%. Ranked by on-time rate it is first of two carriers on the route, where the range runs from Delta at 89.5% to Alaska at 85.8%.
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 |
|---|---|---|---|---|---|
| Delta Air Lines (this page) | 365 | 89.5% | 47 min | 3.29% | A− |
| Alaska Airlines | 1,047 | 85.8% | 58 min | 1.91% | A |
Flight by flight
Delta flight numbers on KOA to SEA
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Departure window
When Delta runs best on this route
Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 365 flights.
The overnight block holds up unusually well at 89.5% on time across 365 flights. Red-eyes fly into empty airspace and empty gates, and they are the first rotation of the aircraft's day rather than the last. The 8pm–5am window is the busiest, with 365 flights scheduled in it.
Across the year
Delta on KOA to SEA through the year
- Jul–Sep 202530 flights93.3%
- Oct–Dec 202592 flights92.0%
- Jan–Mar 202690 flights82.8%
- Apr–Jun 202691 flights93.3%
- Jul–Sep 202662 flights87.9%
Scale runs 75% to 100%.
Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 89.5% on time across 365 flights.
Delta on KOA to SEA did not run the same all year. Its best quarter was Jul–Sep 2025 at 93.3% on time and its weakest Jan–Mar 2026 at 82.8%, a swing of 11 points on roughly 73 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, Tuesday is the strongest day at 96.1% on time and Wednesday the weakest at 82.4%, a spread of 14 points.
Arrival by arrival
How late Delta on KOA to SEA runs when it is late
Delta on KOA to SEA often beats the schedule: 189 of 352 completed flights, 54%, arrived 15 minutes or more early. The 37 late arrivals split 15 under half an hour, 12 between 30 and 60 minutes, and 10 an hour or more.
- 15+ min early189 flights53.7%
- Within 15 min126 flights35.8%
- 15–29 min late15 flights4.3%
- 30–59 min late12 flights3.4%
- 1–2 hours late8 flights2.3%
- 2+ hours late2 flights0.6%
Scale runs 0% to 100%.
Share of 352 completed flights by arrival against schedule.
A late pushback is often recovered here: of 38 departures that left 15 minutes late or more, 14 still arrived on time. 13 flights left on time and still arrived late.
The worst days
Worst days for Delta on KOA to SEA
The latest arrival of the period was on 5 August 2026, 2 hours 35 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The same cause led on three of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 5 August 2026 | 2 hours 35 minutes | Late-arriving aircraft |
| 4 January 2026 | 2 hours 32 minutes | Late-arriving aircraft |
| 11 September 2025 | 1 hour 41 minutes | Carrier |
| 23 May 2026 | 1 hour 39 minutes | Carrier |
| 3 January 2026 | 1 hour 30 minutes | Late-arriving aircraft |
Delay causes
Why Delta runs late on this route
Carrier accounts for 58% of the 1,719 delay minutes carriers reported here, and the remaining four split what is left.
- 58%Carrier
- 22%Late-arriving aircraft
- 21%National Airspace System
The largest share of delay minutes, 58%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 995 of the 1,719 delay minutes reported here. The split is drawn from 1,719 reported delay minutes.
Cancellations run at 3.29%, against 1.89% nationally. That is about 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
Badly late arrivals are rare here: only 2.8% 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.
At 2,688 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
The return leg is a different operation and performs like one: it runs 76.1% on time across 365 flights, 13 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 13 points of difference.
One caution: this is a thin sample. 365 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 Delta on KOA to SEA
Put together: the delay figures matter less here than the 3.29% cancellation rate. A late arrival costs you roughly 45 minutes; a cancelled flight costs you the day. Book the 8pm–5am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 352 completed flights over 12 months sit behind that.
Related
Where to go next
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.