# Marseille, France → London, UK RTT

🇫🇷 **Marseille, France (MRS)** → 🇬🇧 **London, UK (LON)**

Measurement round: `2026-08-16T04:07:28Z`.

For round 2026-08-16T04:07:28Z, the Marseille-to-London ICMP echo run averaged 18.9 ms over 50 probes, with a minimum of 18.41 ms and a maximum of 20.09 ms. No packets were lost, and the 0.42 ms standard deviation with 0.34 ms jitter points to very steady delivery.

Within the 19 outbound routes measured from Marseille, this pair ranks third by average latency. The median variability-to-average ratio across that route set is 3.28%, and this route's own ratio is below that level, so the low average is accompanied by equally consistent sample-to-sample behavior.

London is the western anchor of the Northwest European corridor, while Marseille is a Mediterranean cable landing hub, making this a useful westbound corridor for traffic coming ashore in southern France. The measured average is 1.93 times the theoretical fiber-floor latency, corresponding to a fiber-efficiency value of 51.9%. As an ICMP round-trip reading, it describes the network path's delay profile rather than end-user application quality.

## Latency Summary

| Metric               | Value                                          |
| -------------------- | ---------------------------------------------- |
| RTT                  | **18.9 ms**                                    |
| Jitter               | **0.34 ms**                                    |
| Packet Loss          | **0%**                                         |
| Standard Fiber Floor | **9.82 ms**                                    |
| Fiber Efficiency     | **51.9%**                                      |
| Latency Tier         | Ultra-Low                                      |
| Source Region        | [Europe](/docs/network/latency/regions/europe) |
| Destination Region   | [Europe](/docs/network/latency/regions/europe) |

## 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.

## 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](#about-this-measurement) for citation guidance.

## Theoretical Fiber Latency

The public physical reference uses the GeoNames city centres for [Marseille](https://www.geonames.org/2995469) (43.29695, 5.38107) and [London](https://www.geonames.org/2643743) (51.50853, -0.12574). It does not disclose either facility address.

| Physical Reference                            | Value          |
| --------------------------------------------- | -------------- |
| WGS-84 geodesic distance                      | **1,002.4 km** |
| Vacuum RTT floor                              | **6.69 ms**    |
| Standard fiber RTT floor ($n_g=1.4679$)       | **9.82 ms**    |
| Low-latency fiber material floor              | **9.78 ms**    |
| Engineering floor (5% path allowance)         | **10.31 ms**   |
| Research 1.33× mapped-fiber reference         | **13.06 ms**   |
| Estimated unamplified path loss               | **210.5 dB**   |
| Transparent optical spans / inline amplifiers | **14 / 13**    |
| Published RTT inflation over fiber floor      | **1.93×**      |

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](/docs/network/latency/theoretical-fiber-latency).

## Stability & Trend

The current measurement round (2026-08-16T04:07:28Z) collected 50 ICMP echo samples on this route. Distribution statistics from that round:

| Round Statistic    | Value        |
| ------------------ | ------------ |
| Minimum RTT        | **18.41 ms** |
| Average RTT        | **18.9 ms**  |
| Maximum RTT        | **20.09 ms** |
| Standard deviation | **0.42 ms**  |
| Stdev / average    | **2.2%**     |

## Route Context

* Departure PoP: [Marseille (MRS)](/docs/network/latency/mrs-marseille)
* Destination PoP: [London (LON)](/docs/network/latency/lon-london)
* Region overview: [Europe](/docs/network/latency/regions/europe) → [Europe](/docs/network/latency/regions/europe)
* Full global matrix: [Backbone Latency Matrix](/docs/network/latency)
* Physical methodology: [Theoretical Fiber Latency](/docs/network/latency/theoretical-fiber-latency)

## Related City-Pair Routes

**Reverse direction**

* [London to Marseille latency and RTT](/docs/network/latency/pairs/lon-mrs-rtt) — 17.9 ms

**Fastest routes departing Marseille (MRS)**

* [Marseille to Paris latency and RTT](/docs/network/latency/pairs/mrs-par-rtt) — 8.9 ms
* [Marseille to Frankfurt latency and RTT](/docs/network/latency/pairs/mrs-fra-rtt) — 16 ms
* [Marseille to Amsterdam latency and RTT](/docs/network/latency/pairs/mrs-ams-rtt) — 20.3 ms
* [Marseille to Berlin latency and RTT](/docs/network/latency/pairs/mrs-ber-rtt) — 20.6 ms
* [Marseille to Moscow latency and RTT](/docs/network/latency/pairs/mrs-mow-rtt) — 49.6 ms

**Fastest routes arriving at London (LON)**

* [Amsterdam to London latency and RTT](/docs/network/latency/pairs/ams-lon-rtt) — 5.2 ms
* [Paris to London latency and RTT](/docs/network/latency/pairs/par-lon-rtt) — 6.4 ms
* [Frankfurt to London latency and RTT](/docs/network/latency/pairs/fra-lon-rtt) — 12.9 ms
* [Berlin to London latency and RTT](/docs/network/latency/pairs/ber-lon-rtt) — 15.2 ms
* [Moscow to London latency and RTT](/docs/network/latency/pairs/mow-lon-rtt) — 42.4 ms

**Same corridor (Europe → Europe)**

* [London to Amsterdam latency and RTT](/docs/network/latency/pairs/lon-ams-rtt) — 5.2 ms
* [Amsterdam to Frankfurt latency and RTT](/docs/network/latency/pairs/ams-fra-rtt) — 5.9 ms
* [Frankfurt to Amsterdam latency and RTT](/docs/network/latency/pairs/fra-ams-rtt) — 5.9 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](/opendata/latency/). Per-pair files are available at `/opendata/latency/latest/pairs/mrs-lon.pings.{csv,json,yaml}`. When citing, include the route, the measurement round timestamp, and the dataset version — for example: "Hats Network latency dataset, Marseille → London round 2026-08-16T04:07:28Z, CC BY 4.0".

***

*Data auto-generated on August 16, 2026. Explore the [full interactive latency matrix](/docs/network/latency) or browse more [city-pair routes](/docs/network/latency/pairs).*

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## License and attribution

- **Canonical source:** [View the human-readable HTML page](https://hatsnet.io/docs/network/latency/pairs/mrs-lon-rtt).
- **Original documentation:** © Hats Network Inc., licensed under [CC BY-SA 4.0](https://creativecommons.org/licenses/by-sa/4.0/).
- **Public latency data:** © Hats Network Inc., licensed under [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/).
- **Full terms:** [Content and Data License](https://hatsnet.io/docs/legal/content-and-data-license) — includes attribution requirements, third-party material, trademarks, source code and other exclusions.