# Johannesburg, South Africa → London, UK RTT

🇿🇦 **Johannesburg, South Africa (JNB)** → 🇬🇧 **London, UK (LON)**

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

Johannesburg to London averaged 158 ms across 50 replies. The observed range was 151.59 to 170.89 ms; these figures describe one probe round, not a long-term service target.

This is number 1 of 19 outgoing routes by average RTT. That ranking compares different destinations and is not adjusted for distance.

## Latency Summary

| Metric               | Value                                          |
| -------------------- | ---------------------------------------------- |
| RTT                  | **158 ms**                                     |
| Jitter               | **3.47 ms**                                    |
| Packet Loss          | **0%**                                         |
| Standard Fiber Floor | **88.52 ms**                                   |
| Fiber Efficiency     | **56%**                                        |
| Latency Tier         | Fair                                           |
| Source Region        | [Africa](/docs/network/latency/regions/africa) |
| Destination Region   | [Europe](/docs/network/latency/regions/europe) |

## Ping Measurement Series

50 ICMP echo probes were recorded in this round. Individual replies and their distribution are shown below.

## Download This Route's Data

Download the probe round as CSV, JSON or YAML under CC BY 4.0. [Citation details](#about-this-measurement) include the route and round timestamp.

## Theoretical Fiber Latency

The propagation model uses public city-centre coordinates from GeoNames: [Johannesburg](https://www.geonames.org/993800) (-26.20227, 28.04363) and [London](https://www.geonames.org/2643743) (51.50853, -0.12574). These are not facility coordinates or a surveyed cable path.

| Physical Reference                            | Value          |
| --------------------------------------------- | -------------- |
| WGS-84 geodesic distance                      | **9,039.3 km** |
| Vacuum RTT floor                              | **60.3 ms**    |
| Standard fiber RTT floor ($n_g=1.4679$)       | **88.52 ms**   |
| Low-latency fiber material floor              | **88.16 ms**   |
| Engineering floor (5% path allowance)         | **92.96 ms**   |
| Research 1.33× mapped-fiber reference         | **117.73 ms**  |
| Estimated unamplified path loss               | **1898.3 dB**  |
| Transparent optical spans / inline amplifiers | **119 / 118**  |
| Published RTT inflation over fiber floor      | **1.78×**      |

The span count assumes 80 km optical spans. Attenuation is a power-loss term, not a propagation delay. See the [model assumptions and equations](/docs/network/latency/theoretical-fiber-latency).

## Stability & Trend

Statistics from the same 50 replies. They describe this probe round, not continuous historical monitoring.

| Round Statistic    | Value         |
| ------------------ | ------------- |
| Minimum RTT        | **151.59 ms** |
| Average RTT        | **158 ms**    |
| Maximum RTT        | **170.89 ms** |
| Standard deviation | **4.48 ms**   |
| Stdev / average    | **2.8%**      |

## Route Context

* Departure PoP: [Johannesburg (JNB)](/docs/network/latency/jnb-johannesburg)
* Destination PoP: [London (LON)](/docs/network/latency/lon-london)
* Region overview: [Africa](/docs/network/latency/regions/africa) → [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 Johannesburg latency and RTT](/docs/network/latency/pairs/lon-jnb-rtt): 179.6 ms

**Fastest routes departing Johannesburg (JNB)**

* [Johannesburg to Amsterdam latency and RTT](/docs/network/latency/pairs/jnb-ams-rtt): 163.2 ms
* [Johannesburg to Paris latency and RTT](/docs/network/latency/pairs/jnb-par-rtt): 164.4 ms
* [Johannesburg to Frankfurt latency and RTT](/docs/network/latency/pairs/jnb-fra-rtt): 166 ms
* [Johannesburg to Marseille latency and RTT](/docs/network/latency/pairs/jnb-mrs-rtt): 172 ms
* [Johannesburg to Berlin latency and RTT](/docs/network/latency/pairs/jnb-ber-rtt): 172.1 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
* [Marseille to London latency and RTT](/docs/network/latency/pairs/mrs-lon-rtt): 18.9 ms

**Same corridor (Africa → Europe)**

* [Johannesburg to Moscow latency and RTT](/docs/network/latency/pairs/jnb-mow-rtt): 200.7 ms

## About This Measurement

These ICMP measurements cover the two backbone endpoints. Access networks, routing policy and load can change an end user's result. A probe round is not an SLA.

The underlying replies are available under **CC BY 4.0** in the [Hats Network latency dataset](/opendata/latency/). Per-pair files are available at `/opendata/latency/latest/pairs/jnb-lon.pings.{csv,json,yaml}`. Cite the route, round timestamp and dataset version. Example: "Hats Network latency dataset, Johannesburg → London round 2026-08-16T04:07:28Z, CC BY 4.0".

***

*Round published August 16, 2026. See 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/jnb-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.