LHR to SNN flight delays
1,387 flights · March 2025 – August 2026 · UK Civil Aviation Authority
73.28%
Arrived on time
Within 15 minutes of schedule
0.72%
Cancelled
Share of scheduled flights
—
When late, late by
Average across delayed arrivals
14 min
Delay per flight
Averaged over every flight flown
What the record says about this route
The season swings this route hard. In February it ran 38.8 points more punctual than in December — a difference bigger than the one between the best and worst airlines on most routes. If the date is flexible, it is worth more than the carrier.
Only Aer Lingus flies this route in the published record, so there is no choice to weigh — the route's figures and the airline's are the same figures.
Flights from London to Shannon run late more often than the average route, though not severely.
Which airline should you fly on this route?
Over March 2025 – August 2026, Aer Lingus arrived on time most often on LHR to SNN. Flights ran closest to schedule in February and worst in December.
Every airline on LHR to SNN
Ranked by how many flights each one operated. A carrier with fewer than 100 flights in the period is listed but not graded.
| Airline | Flights | On time | Cancelled | Avg delay | Grade |
|---|---|---|---|---|---|
| Aer Lingus | 1,387 | 73.28% | 0.72% | — | C |
Month by month
Share of flights that arrived within 15 minutes of schedule, by month flown.
The return leg
SNN to LHR Shannon back to London 77.75% on time COther routes from London
Common questions
Are flights from London to Shannon usually delayed?
73.28% of flights on the LHR to SNN route arrived within 15 minutes of schedule, so roughly 3 in every ten arrived late. That is worse than the average route in this record.
Which airlines fly from London to Shannon?
Only Aer Lingus appears in the published record on this route, with 1,387 flights and 73.28% arriving on time.
How often are LHR to SNN flights cancelled?
0.72% of scheduled flights did not operate — about 7 in every thousand. That is in the normal range.
What is the best month to fly London to Shannon?
February, when 88.8% of flights arrived on time. The worst was December at 50%.
What these figures do and do not tell you
Everything on this page is counted from the flights that actually operated on LHR to SNN during March 2025 – August 2026, as reported by the airlines to the US Bureau of Transportation Statistics. "On time" is the federal definition: arriving at the gate within 15 minutes of the scheduled time.
A route's record is a description of the past, not a forecast. Weather, air traffic control and the aircraft's earlier flights that day drive most delays, and none of them are predictable from a historical rate. What the record does tell you is whether this route runs late more often than others, and which carrier on it has the better history — which is the part you can actually act on when you book.
Cancellations are counted separately from delays because they are a different problem for a traveller: a late flight still gets you there. How the grade is calculated →