# Seattle, USA → Marseille, France RTT

🇺🇸 **Seattle, USA (SEA)** → 🇫🇷 **Marseille, France (MRS)**

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

In the 2026-08-16T04:07:28Z measurement round, 50 ICMP echo probes from Seattle, USA to Marseille, France returned an average RTT of 141.2 ms, with a minimum of 134.28 ms and a maximum of 166.5 ms. Zero packet loss and 5.32 ms jitter place this route in the Good latency tier.

Ranked 13th among the 19 Seattle outbound routes in the same round, this route shows a standard deviation of 6.79 ms, about 4.8% of its average. That is a bit above the 3.28% median variability for the route set, but the small loss and moderate jitter still suggest a usable intercontinental path.

Against a geodesic distance of 8,707.5 km and a theoretical fiber floor of 85.27 ms, the observed RTT is 1.66 times the floor — a fiber efficiency of 60.4%. The combination of Good-tier latency and no packet loss makes this route a practical candidate for repeated ICMP polling between Seattle and Marseille.

## Latency Summary

| Metric               | Value                                                        |
| -------------------- | ------------------------------------------------------------ |
| RTT                  | **141.2 ms**                                                 |
| Jitter               | **5.32 ms**                                                  |
| Packet Loss          | **0%**                                                       |
| Standard Fiber Floor | **85.27 ms**                                                 |
| Fiber Efficiency     | **60.4%**                                                    |
| Latency Tier         | Good                                                         |
| Source Region        | [North America](/docs/network/latency/regions/north-america) |
| 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 [Seattle](https://www.geonames.org/5809844) (47.60621, -122.33207) and [Marseille](https://www.geonames.org/2995469) (43.29695, 5.38107). It does not disclose either facility address.

| Physical Reference                            | Value          |
| --------------------------------------------- | -------------- |
| WGS-84 geodesic distance                      | **8,707.5 km** |
| Vacuum RTT floor                              | **58.09 ms**   |
| Standard fiber RTT floor ($n_g=1.4679$)       | **85.27 ms**   |
| Low-latency fiber material floor              | **84.93 ms**   |
| Engineering floor (5% path allowance)         | **89.55 ms**   |
| Research 1.33× mapped-fiber reference         | **113.41 ms**  |
| Estimated unamplified path loss               | **1828.6 dB**  |
| Transparent optical spans / inline amplifiers | **115 / 114**  |
| Published RTT inflation over fiber floor      | **1.66×**      |

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        | **134.28 ms** |
| Average RTT        | **141.2 ms**  |
| Maximum RTT        | **166.5 ms**  |
| Standard deviation | **6.79 ms**   |
| Stdev / average    | **4.8%**      |

## Route Context

* Departure PoP: [Seattle (SEA)](/docs/network/latency/sea-seattle)
* Destination PoP: [Marseille (MRS)](/docs/network/latency/mrs-marseille)
* Region overview: [North America](/docs/network/latency/regions/north-america) → [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**

* [Marseille to Seattle latency and RTT](/docs/network/latency/pairs/mrs-sea-rtt) — 141.7 ms

**Fastest routes departing Seattle (SEA)**

* [Seattle to Los Angeles latency and RTT](/docs/network/latency/pairs/sea-lax-rtt) — 25.9 ms
* [Seattle to New York latency and RTT](/docs/network/latency/pairs/sea-nyc-rtt) — 59.5 ms
* [Seattle to Ashburn latency and RTT](/docs/network/latency/pairs/sea-iad-rtt) — 61.5 ms
* [Seattle to Miami latency and RTT](/docs/network/latency/pairs/sea-mia-rtt) — 81.7 ms
* [Seattle to Tokyo latency and RTT](/docs/network/latency/pairs/sea-tyo-rtt) — 85 ms

**Fastest routes arriving at Marseille (MRS)**

* [Paris to Marseille latency and RTT](/docs/network/latency/pairs/par-mrs-rtt) — 8.9 ms
* [Frankfurt to Marseille latency and RTT](/docs/network/latency/pairs/fra-mrs-rtt) — 16.4 ms
* [London to Marseille latency and RTT](/docs/network/latency/pairs/lon-mrs-rtt) — 17.9 ms
* [Amsterdam to Marseille latency and RTT](/docs/network/latency/pairs/ams-mrs-rtt) — 19.6 ms
* [Berlin to Marseille latency and RTT](/docs/network/latency/pairs/ber-mrs-rtt) — 20.2 ms

**Same corridor (North America → Europe)**

* [New York to London latency and RTT](/docs/network/latency/pairs/nyc-lon-rtt) — 63.5 ms
* [New York to Amsterdam latency and RTT](/docs/network/latency/pairs/nyc-ams-rtt) — 68.7 ms
* [New York to Paris latency and RTT](/docs/network/latency/pairs/nyc-par-rtt) — 68.9 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/sea-mrs.pings.{csv,json,yaml}`. When citing, include the route, the measurement round timestamp, and the dataset version — for example: "Hats Network latency dataset, Seattle → Marseille 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/sea-mrs-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.