Galaxy Watch9 vs Apple Watch Series 12: phone, health, battery and price compared

Choose by phone first. Apple's spec page lists only the iPhone for the Apple Watch Series 12: iPhone 11 or later, including the iPhone SE (2nd generation or later), with iOS 27 or later. Samsung's Canadian support table lists Android 13 or higher with at least 1.5GB of RAM for the Galaxy Watch9, and says tablets aren't supported. Samsung writes the name "Galaxy Watch9", with no space, and so does this guide.

This guide is based on Apple's and Samsung's own pages and press releases as of Nov. 1, 2026. We haven't tested either watch.

The cross-platform question

If you carry an iPhone, the Series 12 is the watch the two companies' pages support. The compatibility list on Apple's spec page names only the iPhone.

If you carry an Android phone, the Galaxy Watch9 is the one Samsung supports, with the Android 13 floor above. None of the Samsung pages we read says the Watch9 pairs with an iPhone, so plan on an Android phone. Our own Samsung Galaxy Watch guide covers the full lineup and its phone requirements.

That settles most buyers. The comparison below matters mainly if you are about to switch phones, or if you are buying for someone whose phone you don't know.

Quick comparison

Health features

Apple Watch Series 12

Apple's release says the Series 12 measures heart rate every five seconds, all day, and measures heart rate variability (HRV) up to 24 times more often than before. It adds a Readiness score from 0 to 10 with a recommendation. Apple's Series 12 page says its Sleep score analyzes several factors every night and returns a classification and a score.

Apple also lists workout tracking, sleep tracking, heart health notifications, the ECG app, sleep apnea notifications, Fall Detection and Emergency SOS. Apple says its heart rate sensing showed "the highest accuracy across devices" in its comparison with other wearables. That is Apple's own study, not an independent test.

A few cautions. The spec page describes HRV as measured "as often as every five minutes", which is a different statement from the release's "24 times more often", so we quote each as written. And the redesigned Health app on iPhone, which brings a Health Age feature, arrives "later this year, starting in U.S. English", with no firmer date. Apple's release lists sleep apnea notifications without saying whether they are FDA-cleared. For the blood pressure question, see our piece on Apple's hypertension notifications, which are not a blood pressure reading.

Galaxy Watch9

Samsung's US page says the Watch9 detects signs of moderate to severe obstructive sleep apnea risk by monitoring blood oxygen levels through the night. Samsung's Global Newsroom says the feature earned the world's first De Novo authorization from the US Food and Drug Administration in 2024.

Other features Samsung describes:

• Vitals: tracks overnight signals including heart rate, heart rate variability, respiratory rate, skin temperature and blood oxygen saturation.
• Energy Score: a daily rating of how well you recovered, based on recent sleep, activity and heart rate during sleep.
• Sleep coaching: a program that runs three to four weeks and learns your sleep patterns.
• Fitness Index: an estimate built from body composition and workout history.
• Blood pressure: an estimate only after you calibrate the watch with a cuff, which is sold separately.
• Heart Health Score: Samsung says the focus "is on prevention and healthy habits, not medical diagnosis."

We could not confirm from the pages we read whether the Watch9 has an ECG feature or in which countries. If ECG matters to you, check Samsung's page for your country before buying.

How they line up

Both watches track sleep and flag possible sleep apnea, and each gives a daily score: Readiness on Apple, Energy Score on Samsung. Apple's pitch is measurement frequency, with a heart rate reading every five seconds. Samsung's pitch is its set of overnight signals and a regulatory clearance for its apnea feature that it states outright. Neither company's claims have been checked against the other's, and the health pages are written by the companies that sell the watches.

Battery

Apple rates the Series 12 for up to 24 hours of everyday battery life, up to 38 hours in Low Power Mode and up to 10 hours of workout tracking, according to its release and spec page. Apple says 15 minutes of charging gives up to 12 hours of additional battery.

Samsung's Global Newsroom says the Watch9 has a 390mAh battery, 20% more capacity than the previous generation's. It gives no battery life in hours on the pages we read.

Capacity in mAh and hours of use are different things, and the companies don't test battery the same way, so there is no honest winner here.

Price and availability

Apple says the Series 12 starts at $399 in the US, and its example price is for the 42mm model. It comes in 42mm and 46mm. Pre-orders opened Sept. 9, and it went on sale Friday, Sept. 18.

Samsung's US page, dated Oct. 16, lists the Galaxy Watch9 "From $379.99 or $15.83/mo before trade-in". The page shows 40mm and 44mm options but doesn't say which one the starting price covers. We could not confirm the 44mm price or the LTE price from Samsung's pages. Samsung says LTE works on its own, and that availability depends on your country and carrier. We also have no prices outside the US from these sources.

So treat the $19.01 gap between the two starting prices as a rough guide, and compare the exact size and connectivity you want at checkout.

The assistants

Samsung's page says Google Gemini on the Watch9 helps with answers, tasks and information across apps by voice. Apple's page says Siri AI on the Series 12 is rolling out in English. If you expect to talk to your watch in another language, check current support first. Our Gemini on smartwatches explainer goes into more detail.

Which one to pick

• You use an iPhone: the Series 12. Of the two, it is the only one whose maker lists iPhone support. Torn between Apple models? See Series 12 vs Ultra 4 and our Apple Watch guide.
• You use an Android phone: the Galaxy Watch9, or Google's watch. Read Pixel Watch 5 vs Galaxy Watch9 and our best smartwatch for Android page.
• You are about to switch phone platforms: buy for the phone you will have, because neither company's pages cover the other's phone. Plan to re-buy the watch if you switch.
• Sleep apnea is the priority: both offer it. Samsung states an FDA clearance for its version. Apple's release doesn't.

For how each launch happened, see our coverage of Apple's September event and Samsung's July Unpacked.