RouteRankingIf you are choosing between Irish airports, punctuality data should factor into that decision. We tracked 3,312 departures across Dublin, Cork, Shannon and Knock over the past 60 days to find out which airport gets you away on time most consistently.
The headline finding: Cork Airport is the most reliable departure point among Ireland's major airports, with 88.5% of flights arriving on time. Shannon edges it on raw percentage at 89.9%, but Cork's figure is based on 530 flights compared to Shannon's 148, making it a more robust comparison. Dublin sits at 83.3% across 2,446 flights. Knock is last at 73.3%.
The bigger your sample, the more confidence you can place in the number. Dublin's 83.3% is the most stable figure in this dataset. Cork's 88.5% is the most meaningful of the smaller airports.
How each airport performs
Dublin's lower average reflects the volume and complexity of its operation. It runs more routes, more airlines and more late-evening services than any other Irish airport. That creates more opportunities for delay.
Knock's 73.3% is partly explained by a severe drop-off in evening punctuality, which we cover below. On morning flights, Knock actually performs reasonably well.
Which airlines perform best at each airport
Aer LingusRyanairBAKLM
The airline picture varies significantly by airport.
At Cork, Aer Lingus leads with 94.3% on-time across 239 flights, followed by KLM at 91.8% and Ryanair at 86.7%. Cork is one of the stronger airports for Aer Lingus performance in this dataset.
At Shannon, Aer Lingus also leads at 91.0% from 112 flights, with Ryanair close behind at 89.3% from 107 flights. The two carriers are unusually well matched here.
At Dublin, British Airways leads at 92.4% from 293 flights, ahead of Ryanair at 85.2% from 2,510 flights and Aer Lingus at 81.5% from 772 flights. Aer Lingus at Dublin is the weakest airline performance in this dataset among carriers with significant volume.
At Knock, Aer Lingus performs well at 88.1% but operates fewer flights. Ryanair sits at 69.4% from 122 flights, and is the primary driver of Knock's overall average.
Does departure time matter?
At most airports, yes. At Cork, no.
05:00-08:5909:00-12:5913:00-16:5917:00+
Cork is the standout for consistency. Its on-time percentage stays between 88.7% and 90.9% regardless of when you fly. That is genuinely unusual. Every other airport shows meaningful variation by time of day.
Dublin follows a clear pattern. Early morning flights (before 09:00) arrive on time 91.1% of the time. That drops to 83.3% in the midday window, recovers slightly to 85.4% in the afternoon, then falls to 79.1% for evening departures. If you have a choice, the first flight of the day from Dublin is significantly more reliable than the last.
Knock has the most dramatic drop-off. Morning flights perform at 92.7%, which is the best of any airport in the early window. But evening flights at Knock arrive on time just 34.2% of the time across 38 observations. That is a significant outlier and worth factoring in if you are booking a late departure from Ireland West.
Shannon shows an unusual pattern where performance actually improves through the day, reaching 97.4% for evening flights. However, the evening sample is only 39 flights, so treat that figure as directional rather than definitive.
The best and worst individual flights
The best performing flights in this dataset come from Dublin. FR112 on the Dublin to Gatwick route departs at 06:55 and has arrived on time on every tracked flight. EI164 on Dublin to Heathrow departs at 08:45 and has a 98.4% on-time record across 31 flights.
At the other end, EI266 on the Dublin to Birmingham route departs at 11:45 and arrives on time just 65.2% of the time. That is the worst performing flight with a meaningful sample size in this dataset.
The pattern is consistent with the departure window data. Early morning slots outperform midday and evening across every airport except Cork, where the time of day appears to make little difference.
What this means if you are choosing an airport
If Cork serves your destination, the data makes a straightforward case for using it. It is the most consistent airport in this analysis across every time window and every airline operating there.
If you are flying from Dublin, book the earliest available departure. The gap between a 07:00 and a 19:00 flight from Dublin is roughly 12 percentage points on punctuality. That is meaningful if you are connecting or arriving for a fixed-time commitment.
If you are using Knock, avoid late evening flights where possible. The morning window performs well, but the evening figures are significantly below the national average.
Shannon performs well given its size, and the Ryanair versus Aer Lingus gap there is the smallest of any airport in this dataset.
For full flight-by-flight rankings at each airport, see the route pages:
Frequently Asked Questions
Which Irish airport has the best on-time performance? Based on 60 days of data tracked by RouteRanking, Shannon leads on raw percentage at 89.9%, but Cork's 88.5% from 530 flights is the more reliable figure. Cork is the most consistently punctual airport in this analysis.
Why does Dublin have a lower on-time percentage than Cork or Shannon? Dublin operates significantly more routes, more airlines and more late-evening services. That increases the exposure to delay. The 83.3% figure covers 2,446 flights and is the most stable number in this dataset.
Does it matter what time you fly from Dublin Airport? Yes. Flights before 09:00 arrive on time 91.1% of the time. Evening flights after 17:00 arrive on time 79.1% of the time. The earlier you fly from Dublin, the better your chances.
How does Knock Airport compare to other Irish airports? Knock averages 73.3% on-time, the lowest in this dataset. Morning flights perform well at 92.7%, but evening flights drop to 34.2% based on 38 observations. The overall average is dragged down by late-day performance.
Which airline is most punctual from Irish airports? Aer Lingus leads at Cork (94.3%) and Shannon (91.0%). British Airways leads at Dublin (92.4%) but operates fewer routes. Ryanair is the dominant carrier by volume and sits at 85-89% across most airports, with the exception of Knock where it falls to 69.4%.
How is this data collected? RouteRanking tracks historical flight arrival data via AeroDataBox and updates every morning. On-time is defined as arrival within 15 minutes of scheduled time, consistent with the OAG and Eurocontrol standard. Flights with fewer than 30 observations are excluded from airport-level averages. Shannon and Knock figures should be treated as directional given smaller sample sizes.