ICMP round-trip time from London, UK to Sydney, Australia: 261.9 ms average, 0% packet loss, plus route context from the 2026-08-15T04:03:13Z round.

🇬🇧 London, UK (LON) → 🇦🇺 Sydney, Australia (SYD)

Measurement round: 2026-08-15T04:03:13Z.

For the 2026-08-15T04:03:13Z round, ICMP echo RTT from London to Sydney averaged 261.9 ms over 50 samples, with a minimum of 254.2 ms and a maximum of 301.34 ms. No packets were lost, and the spread was moderate: standard deviation 8.63 ms, jitter 5.38 ms.

The great-circle distance between London and Sydney is 16,988.9 km, and a perfect fiber path would put the round-trip floor near 166.4 ms; the measured average is 1.57 times that floor, giving an effective fiber-path utilization of 63.5%. This route is ranked 19th among the 19 outbound routes in the current set, which is consistent with the exceptional distance involved.

Its variability ratio of about 3.30% sits slightly above the set's median of 3.08%, but zero packet loss and modest jitter still make this a steady high-latency baseline for London-to-Sydney ICMP RTT in this round.

Latency Summary

Metric	Value
RTT	261.9 ms
Jitter	5.38 ms
Packet Loss	0%
Standard Fiber Floor	166.37 ms
Fiber Efficiency	63.5%
Latency Tier	High
Source Region	Europe
Destination Region	Asia Pacific

Ping Measurement Series

The chart below renders the 50-sample ICMP echo measurement round for this route; an accessible table of every sample is included with the chart.

Ping series: LON → SYD

50 ICMP echo samples at 100 ms intervals · round 2026-08-15T04:03:13Z · avg 261.9 ± 1.22 ms (SE)

Sample distribution: box = interquartile range (256.5–264.5 ms), median 259.3 ms · whiskers = min–max · diamond = round average · each dot is one measured sample.

How to read this chart

The shaded band spans the measured minimum to maximum RTT of all samples collected up to that point, and the thin line traces the running average. The final position therefore matches the round statistics exactly — the band only widens when a new extreme sample arrives.

The dashed line is the round average, and the shaded band at the bottom is the theoretical fiber-optic floor (166.4 ms) for this route.

Full 50-sample dataset

Seq	Offset (ms)	RTT (ms)
1	0	278.89
2	100	301.34
3	200	271.85
4	300	262.89
5	400	256.56
6	500	287.69
7	600	270.36
8	700	264.68
9	800	266.41
10	900	258.60
11	1000	258.49
12	1100	259.84
13	1200	259.34
14	1300	255.54
15	1400	261.11
16	1500	270.18
17	1600	260.91
18	1700	264.07
19	1800	257.23
20	1900	254.99
21	2000	254.30
22	2100	257.09
23	2200	262.03
24	2300	257.66
25	2400	259.21
26	2500	255.46
27	2600	270.20
28	2700	267.25
29	2800	267.77
30	2900	266.07
31	3000	259.40
32	3100	256.45
33	3200	255.53
34	3300	255.89
35	3400	259.40
36	3500	260.90
37	3600	258.37
38	3700	257.41
39	3800	257.56
40	3900	261.12
41	4000	256.01
42	4100	254.20
43	4200	259.63
44	4300	259.27
45	4400	265.64
46	4500	258.14
47	4600	255.64
48	4700	255.69
49	4800	255.23
50	4900	255.51

Download This Route's Data

This route's measurement round is published as open data (CC BY 4.0) in CSV, JSON, and YAML. See About This Measurement for citation guidance.

Download this dataset

Per-route ICMP ping series, released under CC BY 4.0. Uncompressed plain text — no decompression step needed.

CSV JSON YAML Full dataset

Theoretical Fiber Latency

The public physical reference uses the GeoNames city centres for London (51.50853, -0.12574) and Sydney (-33.86785, 151.20732). It does not disclose either facility address.

Physical Reference	Value
WGS-84 geodesic distance	16,988.9 km
Vacuum RTT floor	113.34 ms
Standard fiber RTT floor ( $n_g=1.4679$ )	166.37 ms
Low-latency fiber material floor	165.7 ms
Engineering floor (5% path allowance)	174.71 ms
Research 1.33× mapped-fiber reference	221.27 ms
Estimated unamplified path loss	3567.7 dB
Transparent optical spans / inline amplifiers	223 / 222
Published RTT inflation over fiber floor	1.57×

Attenuation is used to estimate the number of 80 km optical spans; it does not directly slow light. See the full theoretical fiber latency, GeoNames, attenuation, and amplifier methodology.

Stability & Trend

The current measurement round (2026-08-15T04:03:13Z) collected 50 ICMP echo samples on this route. Distribution statistics from that round:

Round Statistic	Value
Minimum RTT	254.2 ms
Average RTT	261.9 ms
Maximum RTT	301.34 ms
Standard deviation	8.63 ms
Stdev / average	3.3%

RTT trend

Estimated route stability across the selected time window.

Average: 261.7 ms
Minimum: 259.4 ms
Maximum: 264.5 ms
Average loss: 0.03%

Route Context

Departure PoP: London (LON)
Destination PoP: Sydney (SYD)
Region overview: Europe → Asia Pacific
Corridor overview: Europe to Asia Pacific
Full global matrix: Backbone Latency Matrix
Physical methodology: Theoretical Fiber Latency

Reverse direction

Sydney to London latency and RTT — 260.4 ms

Fastest routes departing London (LON)

London to Amsterdam latency and RTT — 5.1 ms
London to Paris latency and RTT — 7.1 ms
London to Frankfurt latency and RTT — 12.3 ms
London to Berlin latency and RTT — 16.2 ms
London to Marseille latency and RTT — 24.9 ms

Fastest routes arriving at Sydney (SYD)

Melbourne to Sydney latency and RTT — 9.8 ms
Singapore to Sydney latency and RTT — 95.3 ms
Tokyo to Sydney latency and RTT — 101.6 ms
Taipei to Sydney latency and RTT — 131.8 ms
Hong Kong to Sydney latency and RTT — 136.3 ms

Same corridor (Europe → Asia Pacific)

Moscow to Hong Kong latency and RTT — 118.5 ms
Moscow to Taipei latency and RTT — 130.9 ms
Marseille to Singapore latency and RTT — 138.5 ms

About This Measurement

Published RTT reflects best-case backbone path behavior measured with ICMP echo probes between PoPs. End-user latency also depends on local access networks, congestion, routing policy, and traffic engineering. None of these values is an SLA.

The measurement round behind this page is published as open data under CC BY 4.0 in the Hats Network latency dataset. Per-pair files are available at /opendata/latency/latest/pairs/lon-syd.pings.{csv,json,yaml}. When citing, include the route, the measurement round timestamp, and the dataset version — for example: "Hats Network latency dataset, London → Sydney round 2026-08-15T04:03:13Z, CC BY 4.0".

Data auto-generated on August 15, 2026. Explore the full interactive latency matrix or browse more city-pair routes.

London, UK → Sydney, Australia RTT