I raced a half marathon with the Apple Watch Ultra 4 vs Apple Watch Series 12 to test accuracy — here’s what happened
A tech journalist tested the GPS and heart rate accuracy of the newly launched Apple Watch Ultra 4 and Series 12 during the Shoreditch Half Marathon in London. The course featured numerous tight turns, providing a rigorous challenge for the devices' tracking capabilities. The Ultra 4 demonstrated superior GPS accuracy, while the Series 12 offered slightly better heart rate monitoring performance.
- ▪The Apple Watch Ultra 4 and Series 12 were tested during the Shoreditch Half Marathon to evaluate their accuracy in race conditions.
- ▪The Ultra 4 outperformed the Series 12 in GPS accuracy, particularly on the course's many tight twists and turns.
- ▪The Series 12 provided more accurate heart rate readings compared to the Ultra 4, as verified against a Garmin chest strap monitor.
- ▪Both watches registered distances longer than the official 13.1 miles due to the runner taking wide turns and weaving through the crowd.
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| Canonical URL | https://www.tomsguide.com/wellness/smartwatches/i-raced-a-half-marathon-with-the-apple-watch-ultra-4-vs-apple-watch-series-12-to-test-accuracy-heres-what-happened |
| Publication time | Wed, 23 Sep 2026 07:45:00 +0000 |
| Retrieval time | 2026-09-23T07:54:30.574Z |
| Last seen | 2026-09-23T07:54:30.574Z |
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Basis: Derived from the published RSS/Atom feed. Contact: [email protected]. Reviewed: 2026-07-24.
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Wellness Smartwatches I raced a half marathon with the Apple Watch Ultra 4 vs Apple Watch Series 12 to test accuracy — here’s what happened Features By Nick Harris-Fry Published 23 September 2026 Both watches impressed on a twisting course When you purchase through links on our site, we may earn an affiliate commission. Here’s how it works. (Image credit: Future) Copy link Facebook X Reddit Email Share this article 0 Join the conversation Follow us Add us as a preferred source on Google Newsletter Subscribe to our newsletter Last week saw the full launch of the Apple Watch Ultra 4 and Apple Watch Series 12, and both landed on my doorstep just days before I was due to tackle the Shoreditch Half Marathon in east London.It seemed the perfect chance to test the accuracy of both watches in…
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