Route profile
DEN→SJU
Flight reliability, delays and best times to fly from Denver to San Juan, 2,733 miles.
Right now
Aviation weather is not currently a factor.
Aviation weather is not currently a factor.
Route reliability
October 2023 – July 2026
Better than 76% of comparable major US routes (4,598 compared)
Calculated from 916 flights. How this is calculated
DEN → SJU arrives on time 76.7% of the time; the return trip, SJU → DEN, arrives on time 78.0% of the time.
DEN → SJU spends 31.0 minutes on the ground on a 2,733-mile trip: 27.0 minutes from pushback to wheels-up at DEN and 4.0 minutes from touchdown to gate at SJU.
Source: US DOT Bureau of Transportation Statistics · Data covering October 2023 – July 2026
What stands out
Which day you fly matters unusually much here, a wider weekday spread than 98% of 4,467 comparable routes.
83.6% on time on a typical Tuesday, against 66.7% on a Saturday.
Source: FlyerIntel analysis of US DOT BTS data · October 2023 – July 2026 · Ranked against every other route with the same kind of figure and at least 4,467 in the comparison.
What sets this route apart
Where DEN to SJU differs most from similar routes by hour, weekday, month and airline, October 2023 – July 2026.
DEN to SJU struggles most at 9 AM: 76.7% of its flights scheduled then arrive on time, 2.8 points behind the 79.5% on routes of similar length at the same hour. Against all other routes the gap is 7.6 points.
Saturday is the day DEN to SJU slips furthest against routes of similar length, 66.7% on time where they average 78.5%, 11.8 points lower. Against all other routes the gap is 12.4 points.
United Airlines’ flights on DEN to SJU arrive on time 76.7% of the time, 3.5 points below the 80.2% it manages on its routes of similar length. Against all other routes the gap is 3.2 points.
DEN to SJU against comparable routes
October 2023 – July 2026| Measure | This route | Compared with | Them | Gap | Flights behind it |
|---|---|---|---|---|---|
| Hour: 9 AM departures | 76.7% | routes of similar length | 79.5% | −2.8 pts | 906 here, 44,843 there |
| Weekday: Saturday | 66.7% | routes of similar length | 78.5% | −11.8 pts | 141 here, 93,384 there |
| Airline: United Airlines | 76.7% | routes of similar length | 80.2% | −3.5 pts | 906 here, 159,040 there |
Each comparison pools the flights of other routes, with this route’s own left out. Similar length means within 15% of this route’s 2,733 miles, with at least 5 such routes. A bucket is set against the most comparable group that has enough flights: similar length, then the same origin (at least 3 routes), then all other routes. Hours, weekdays and months appear only where both sides have 120 completed flights, and airlines where both have 600. The gap must be at least 2 points and 2 standard errors, and only the largest gap each way is kept per measure. These are differences in the flights counted, not causes.
When it goes wrong
October 2023 – July 2026
35 min late
against a median of 1 min early
Percentiles over 916 operations; cancelled and diverted flights are counted separately.
Will your connection be tight enough?
Layovers at SJU after arriving from DEN.
| Connection time | Chance of missing | Reads as |
|---|---|---|
| 30 min | 46% | Likely to miss |
| 45 min | 22% | High risk |
| 60 min | 12% | Some risk |
| 90 min | 3.8% | Low risk |
| 120 min | 1.7% | Low risk |
This is one leg of a connection. Gate changes and the next flight's own schedule matter too. And a connection can fail before delay is even the question — this route cancels 0.33% of the time and diverts 0.76% of the time, which a late arrival never shows up in.
Chance of missing is the share of 906 arrivals on this route that landed later than the connection time less 30 minutes to reach the next gate.
The worst tenth of arrivals on this route land at least 35 minutes late (90th-percentile gate arrival delay), over 916 operations.
Any other layover length: connection checker.
Why DEN → SJU runs late
October 2023 – July 2026
airspace and airport capacity, including weather-driven flow control
crew, maintenance, boarding and fueling, all within the carrier’s control
the inbound aircraft was late, so this flight started late
weather severe enough to stop this flight specifically
Share of the delay minutes US DOT attributed to each cause for DEN → SJU. Only delays of 15 minutes or more are attributed.
Airlines on this route
Carriers with at least 200 flights, by the airline that operated each one.
| Carrier | Flights | On time | Cancelled | Median delay | Severe |
|---|---|---|---|---|---|
| United Airlines | 916 | 76.7% | 0.33% | -1 min | 3.9% |
Flights on this route
Flight numbers with at least 600 operations here and still on the schedule.
| Flight | Scheduled | Operations | On time |
|---|---|---|---|
| UA1339 United Airlines | 9:50 AM | 916 | 76.7% |
Weekly and seasonal patterns
By day of week
Tuesday is historically the most reliable day and Saturday the least, a gap of 16.9 percentage points.
Reliability over time
October 2023 – July 2026
Over the most recent 12 months (2025-08 to 2026-07), on-time arrivals averaged 82.9% against 69.1% in the 12 months before — improving by 13.8 percentage points.
Data and methodology
Calculated by FlyerIntel from 916 DEN → SJU flight records from the US DOT Bureau of Transportation Statistics, covering October 2023 – July 2026. Late means 15 or more minutes past scheduled arrival; cancelled and diverted flights are left out of on-time rates.
Full methodology · Data sources · Report a problem
Related research: How Long a Layover Needs to Be · Two Airlines on One Route · Best Time of Day to Fly From Major US Airports
Analysis last recomputed