SYD to LHR flight delays
Sydney (Mascot) (SYD) London (LHR)
422 flights · January 2025 – August 2026 · Australian Government BITRE and UK Civil Aviation Authority
66.59%
Arrived on time
Within 15 minutes of schedule
1.42%
Cancelled
Share of scheduled flights
—
When late, late by
Average across delayed arrivals
36 min
Delay per flight
Averaged over every flight flown
What the record says about this route
Which airline you fly changes the odds here. British Airways arrived on time 27.7 points more often than Qantas over the same period on the same route — same airports, same weather, same air traffic control. A gap that survives all of that is about how the two airlines are run.
The season swings this route hard. In March it ran 26.7 points more punctual than in May — 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.
The two directions do not behave alike. LHR to SYD arrives on time 9.7 points more often than the outbound. Delay accumulates through the flying day, so whichever direction is scheduled later tends to carry the worse record — which is an argument for booking the morning departure if the choice exists.
This route does worse than its own airport. SYD as a whole runs 13.2 points more punctual than these flights, which points at something specific to the route — the time of day it is scheduled, or the aircraft that feed it — rather than the airport.
Which airline should you fly on this route?
Over January 2025 – August 2026, British Airways arrived on time most often on SYD to LHR. Qantas was late most often. Flights ran closest to schedule in March and worst in May.
Every airline on SYD to LHR
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 |
|---|---|---|---|---|---|
| Qantas | 212 | 52.86% | 0.94% | — | F |
| British Airways | 210 | 80.58% | 1.9% | — | C |
Month by month
Share of flights that arrived within 15 minutes of schedule, by month flown.
The return leg
LHR to SYD London back to Sydney (Mascot) 76.3% on time COther routes from Sydney (Mascot)
Common questions
Are flights from Sydney (Mascot) to London usually delayed?
66.59% of flights on the SYD to LHR 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 airline is most on time from Sydney (Mascot) to London?
British Airways, at 80.58% on time across 210 flights. The least punctual on the route was Qantas at 52.86%.
How often are SYD to LHR flights cancelled?
1.42% of scheduled flights did not operate — about 14 in every thousand. That is in the normal range.
What is the best month to fly Sydney (Mascot) to London?
March, when 76.7% of flights arrived on time. The worst was May at 50%.
What these figures do and do not tell you
Everything on this page is counted from the flights that actually operated on SYD to LHR during January 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 →