Carrier route record
AAMIA→SJU
American Airlines · Miami to San Juan
- Flights
- 2,078
- Period
- July 2025 to June 2026
- Share of route
- 79%
- Carriers
- 3
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with American Airlines.
American on MIA to SJU lands a B+, about a point worse than the national rate of 77.6%. About one flight in four 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 2,078 flights, with a median arrival 6 minutes early.
The US average over the same twelve months is 77.6%, so there is little to separate American on MIA to SJU from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
76.8%
Arrivals under 15 minutes late, of 2,065 completed flights
Avg delay
71 min
Across delayed arrivals only, not all flights
Cancelled
0.53%
National rate is 1.81%
Whole route
74.7%
Every carrier on MIA to SJU, 2,636 flights
These figures cover 2,078 flights between July 2025 and June 2026. Beyond the headline rate, 8.6% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.
Carrier by carrier
American against every carrier on MIA to SJU
American flew 2,078 of the 2,636 flights on MIA to SJU, most of the route. Its 76.8% on time is 2 points better than the route as a whole, which runs 74.7%. Ranked by on-time rate it is first of three carriers on the route, where the range runs from American at 76.8% to Spirit at 55.8%. One 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 |
|---|---|---|---|---|---|
| American Airlines (this page) | 2,078 | 76.8% | 71 min | 0.53% | B+ |
| Frontier Airlines | 379 | 71.5% | 85 min | 1.85% | C |
| Spirit Airlinesthin sample | 179 | 55.8% | 96 min | 3.91% | D− |
Flight by flight
American flight numbers on MIA to SJU
Departure window
When American runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 30 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–8am249 flights92.3%
- 8am–11am647 flights86.9%
- 11am–2pm449 flights67.6%
- 2pm–5pm364 flights69.4%
- 5pm–8pm207 flights70.7%
- 8pm–5am162 flights62.1%
Scale runs 55% to 100%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 62.1% on time, against 92.3% 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 8am–11am window is the busiest, with 647 flights scheduled in it.
Across the year
American on MIA to SJU through the year
July is the worst month at 67.1% on time, 21 points below May, the best at 88.3%. 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. March was the busiest month here, with 212 flights.
Across the week, Wednesday is the strongest day at 82.0% on time and Sunday the weakest at 67.2%. 15 points is a smaller lever than departure hour, but it is free.
Delay causes
Why American runs late on this route
One category carries most of the weight here. Carrier accounts for 45% of the 34,000 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.
- 45%Carrier
- 39%Late-arriving aircraft
- 12%National Airspace System
- 4%Extreme weather
- 0%Security
39% 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 34,000 reported delay minutes here, that single category outweighs weather by 10 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 34,081 reported delay minutes.
The largest share of delay minutes, 45%, 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 15,000 of the 34,000 delay minutes reported here.
Cancellations are rare at 0.53%, 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
8.6% 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 1,045 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 78.5% on time across 2,079 flights, within 2 points 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 2,078 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 American on MIA to SJU
Put together: the calendar is the biggest lever here, not the carrier or the hour. May runs 88.3% on time and July 67.1%, a swing of 21 points. If the dates move at all, move them out of July before you think about anything else. 2,065 completed flights over 12 months sit behind that.
Related
Where to go next
- MIA to SJU, every carrier
- American on SJU to MIA, the return leg
- Frontier Airlines on MIA to SJU71.5%
- Spirit Airlines on MIA to SJU55.8%
- American Airlines network-wide record
- Miami International (MIA) delay statistics
- Luis Munoz Marin International (SJU) 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.