# Sydney, Australia → Seattle, USA RTT

🇦🇺 **Sydney, Australia (SYD)** → 🇺🇸 **Seattle, USA (SEA)**

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

During the 2026-08-16T04:07:28Z measurement round, ICMP echo RTT from Sydney, Australia, to Seattle, USA averaged 161.9 ms over 50 samples, with a minimum of 153.84 ms and a maximum of 176.63 ms. Packet loss was 0%.

For the 12,453.7 km great-circle separation, that average is 1.33 times the theoretical fiber-floor delay and corresponds to 75.3% fiber efficiency. The result placed 7th among the 19 outbound routes measured from the Sydney gateway, putting it in the faster portion of the group.

The standard deviation was 5.72 ms and jitter was 3.81 ms, about 3.5% of the average, which sits close to the network's median variability of 3.3%. Zero packet loss and a 22.79 ms difference between best and worst samples indicate a steady trans-Pacific latency profile under the test conditions.

## Latency Summary

| Metric               | Value                                                        |
| -------------------- | ------------------------------------------------------------ |
| RTT                  | **161.9 ms**                                                 |
| Jitter               | **3.81 ms**                                                  |
| Packet Loss          | **0%**                                                       |
| Standard Fiber Floor | **121.96 ms**                                                |
| Fiber Efficiency     | **75.3%**                                                    |
| Latency Tier         | Fair                                                         |
| Source Region        | [Asia Pacific](/docs/network/latency/regions/asia-pacific)   |
| Destination Region   | [North America](/docs/network/latency/regions/north-america) |

## 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 [Sydney](https://www.geonames.org/2147714) (-33.86785, 151.20732) and [Seattle](https://www.geonames.org/5809844) (47.60621, -122.33207). It does not disclose either facility address.

| Physical Reference                            | Value           |
| --------------------------------------------- | --------------- |
| WGS-84 geodesic distance                      | **12,453.7 km** |
| Vacuum RTT floor                              | **83.08 ms**    |
| Standard fiber RTT floor ($n_g=1.4679$)       | **121.96 ms**   |
| Low-latency fiber material floor              | **121.47 ms**   |
| Engineering floor (5% path allowance)         | **128.07 ms**   |
| Research 1.33× mapped-fiber reference         | **162.2 ms**    |
| Estimated unamplified path loss               | **2615.3 dB**   |
| Transparent optical spans / inline amplifiers | **164 / 163**   |
| Published RTT inflation over fiber floor      | **1.33×**       |

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        | **153.84 ms** |
| Average RTT        | **161.9 ms**  |
| Maximum RTT        | **176.63 ms** |
| Standard deviation | **5.72 ms**   |
| Stdev / average    | **3.5%**      |

## Route Context

* Departure PoP: [Sydney (SYD)](/docs/network/latency/syd-sydney)
* Destination PoP: [Seattle (SEA)](/docs/network/latency/sea-seattle)
* Region overview: [Asia Pacific](/docs/network/latency/regions/asia-pacific) → [North America](/docs/network/latency/regions/north-america)
* 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**

* [Seattle to Sydney latency and RTT](/docs/network/latency/pairs/sea-syd-rtt) — 161.3 ms

**Fastest routes departing Sydney (SYD)**

* [Sydney to Melbourne latency and RTT](/docs/network/latency/pairs/syd-mel-rtt) — 9.8 ms
* [Sydney to Singapore latency and RTT](/docs/network/latency/pairs/syd-sin-rtt) — 94.5 ms
* [Sydney to Tokyo latency and RTT](/docs/network/latency/pairs/syd-tyo-rtt) — 101.3 ms
* [Sydney to Taipei latency and RTT](/docs/network/latency/pairs/syd-tpe-rtt) — 131.7 ms
* [Sydney to Hong Kong latency and RTT](/docs/network/latency/pairs/syd-hkg-rtt) — 135.7 ms

**Fastest routes arriving at Seattle (SEA)**

* [Los Angeles to Seattle latency and RTT](/docs/network/latency/pairs/lax-sea-rtt) — 26.9 ms
* [New York to Seattle latency and RTT](/docs/network/latency/pairs/nyc-sea-rtt) — 58.7 ms
* [Ashburn to Seattle latency and RTT](/docs/network/latency/pairs/iad-sea-rtt) — 62.3 ms
* [Miami to Seattle latency and RTT](/docs/network/latency/pairs/mia-sea-rtt) — 81.9 ms
* [Tokyo to Seattle latency and RTT](/docs/network/latency/pairs/tyo-sea-rtt) — 84.8 ms

**Same corridor (Asia Pacific → North America)**

* [Tokyo to Los Angeles latency and RTT](/docs/network/latency/pairs/tyo-lax-rtt) — 101.2 ms
* [Taipei to Seattle latency and RTT](/docs/network/latency/pairs/tpe-sea-rtt) — 115.8 ms
* [Hong Kong to Seattle latency and RTT](/docs/network/latency/pairs/hkg-sea-rtt) — 131.6 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/syd-sea.pings.{csv,json,yaml}`. When citing, include the route, the measurement round timestamp, and the dataset version — for example: "Hats Network latency dataset, Sydney → Seattle 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/syd-sea-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.