Samsung’s new smartwatch, the Galaxy Watch4, is unremarkable in many ways.

It’s plagued by the same smartwatch problems that the other leading brand—ahem, Apple Watch—tends to face: daily charging, heavy reliance on a smartphone and an inundation of health graphs and stats, more than most of us non-medical-professional folks know what to do with.

However, the Watch4, available Aug. 27 for $250 and $300 with LTE cellular, is a big departure for a Samsung watch. It’s the first to run Google’s revamped software for wearables, Wear OS 3. That means the Watch4 can run native Google services, such as Google Maps and Google Pay, and download watch apps from the Google Play store.

The partnership between Google and Samsung makes sense. Samsung is eager to catch up to Apple, the longtime smartwatch leader. The most recent estimates indicate that the Apple Watch maker has captured 33% of the global market, according to Counterpoint Research. Samsung accounts for just 8% of smartwatches, while Fitbit has 4.5% world-wide.

The Galaxy Watch4 Classic ($350), shown with a dark watch face, features a rotating bezel for scrolling, while the Galaxy Watch4 ($250) has a slimmer profile.

Photo: Nicole Nguyen/The Wall Street Journal

Previous Galaxy Watch models were powered by Tizen, a Samsung-designed operating system. Google couldn’t get Wear OS to take off with other smartwatch makers. The result? A confusing software ecosystem, with developers shrugging their shoulders and not really supporting many apps for either. Google says by merging platforms with Samsung, the joint effort also sped up app loading times and lengthened battery life.

And in my tests, apps did seem zippier, though the device’s battery, rated for 40 hours, needed a top-up charge every 24 hours, especially after a day of GPS-based workouts and a night of sleep tracking.

While the Galaxy Watch4 is a work in progress, it’s the best smartwatch Android users can buy right now—and the first Samsung wearable that potentially challenges Apple’s smartwatch dominance.

Google + Samsung

The Galaxy Watch4 introduces more synergy with Android phones. The watch will mirror phone settings such as Do Not Disturb, for example. There’s a new Apple Watch-esque display showing installed apps as floating bubbles, and a new Tiles menu that offers quick access to your favorite apps.

The processor is fast, the display is vibrant and the hardware is sleek and feels good on your wrist—even my teeny tiny one.

But the hardware is very different from Apple’s wearable. You might have noticed that Samsung’s smartwatches aren’t square like Apple’s, but more of a traditional circle. And instead of scrolling with a dial, you glide your finger around the edge of the display. For $100 more, you can opt for the Watch4 Classic, which has a raised rotating bezel.

The physical design isn’t much of a change from previous models. What’s distinct about the Watch4 is its ability to run a larger selection of apps via Google’s Play store.

The Galaxy Watch4 Classic, which comes in 42 mm and 46 mm sizes, is the larger and heavier of the two new models because of its rotatable bezel.

Photo: Nicole Nguyen/The Wall Street Journal

Before Wear OS, Samsung’s watches had no native maps app. Google Maps on the Watch4 offers turn-by-turn directions for driving, walking and biking, and can buzz your wrist when you need to change streets. Unfortunately, it doesn’t show public transportation as a mode of transit on the watch. That’s where Citymapper—downloadable via the Play store—comes in. The app can show directions and schedules for getting around major cities in Europe, Asia, the U.S. and Canada.

Some apps also work without a phone. Spotify says it’s bringing offline listening for music and podcasts to Wear OS in the coming weeks. Komoot, for a $30 one-time fee, offers offline maps for hiking, biking and running. Calm’s watch app has breath-based programs that don’t require a network connection.

Not all apps run smoothly, however—including Google’s own. I wanted to see what a pure Google experience would be like, down to Google’s Alarm app. The alarm rang on the watch, but no alert showed up on its screen. I powered the device off and on again. The angry ringing continued. Finally, I dug into the watch’s apps to find Google Alarm and opened it to disable the sound.

When enabled, the always-on display shows the time in black and white. Raise your wrist to activate the color touch screen.

Photo: Nicole Nguyen/The Wall Street Journal

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Despite the companies’ platform unification, the watch still works best with Samsung apps—and when paired with a Samsung smartphone. You can’t uninstall Samsung Pay, even if you want to use Google Pay on the watch. When I paired the watch with a Google Pixel 5 phone, the Samsung Health app wouldn’t let me log in. A company spokeswoman said that the review units provided to me by Samsung were running prerelease software. A software update, coming soon, should patch some of the bugs.

Right now, you can’t even replace the shortcut for Bixby, Samsung’s voice-enabled virtual assistant, with Google Assistant. “We’re working closely with Google to bring popular Google services to Galaxy Watch4. We will share more details once they’re ready,” the spokeswoman said. (Several Fitbit smartwatches already have Google Assistant on board.)

Health + Fitness

The Watch4 does have some new distinctive health capabilities. Snoring detection, which uses the paired smartphone’s microphone to capture the snores, successfully recorded eight distinct honk-shhh sessions one night—but they belonged to my husband. Samsung said it can’t distinguish snores between the watch wearer and a co-sleeper if the two people are close to each other. The spokeswoman recommended putting the phone as close to the watch wearer as possible.

The Galaxy Watch includes a snoring-detection feature that uses the microphone from a paired smartphone to capture audio snippets.

Photo: Nicole Nguyen/The Wall Street Journal

The watch can also send a gentle electrical current through your body (aka “bioelectrical impedance analysis”) to calculate body composition. It measured my body fat percentage at 10% more than my at-home Fitbit Aria smart scale, which does the same. The Samsung spokeswoman said many factors can influence the result, such as whether you recently took a shower, exercised or drank a big gulp of water, and how your arms are positioned while taking the measurement. Ideally, you take a measurement at the same time of day and on an empty stomach.

You can record many types of workouts, from hiking to elliptical training. The freshwater and saltwater resistance, onboard GPS and heart-rate sensors mean it’s easy to track runs, bikes and swims without a phone. The Komoot app’s offline mapping capabilities on the Watch4 might convert some Garmin wearers looking for a more phone-friendly pairing.

But choosing the right workout app isn’t always straightforward.

The Google Fit app recorded the distance and time of a run correctly, but a third of the route didn’t show up on the map. So I switched to the default Samsung Health app. The only way to export the Samsung workout data is through a Strava integration. While I’m a big fan of the training platform, the Samsung Health app stopped syncing to Strava after my first run. No amount of account reconnecting and phone restarting fixed the issue. The coming software update addresses the Samsung/Strava integration, the spokeswoman said.

I eventually decided to rely instead on Strava’s Wear OS app to record activities—but workouts are limited to runs and bike rides, even though Watch4 is capable of tracking pool and open-water swims.

A new Tiles menu offers quick access to favorite apps with a swipe to the left. CREDIT: NICOLE NGUYEN/THE WALL STREET JOURNAL The Wall Street Journal Interactive Edition

If you’re an athlete, I’d still probably steer you to a Garmin or Fitbit for the data portability and fitness-focused features. But the marriage between Samsung and Google, rocky start or not, signals better Android-compatible smartwatch momentum than ever before. The hope is that the combination of Samsung’s great hardware and Google’s native software draws in developers who will refine their apps for the platform and turn this watch—and future Wear OS watches—into something awesome.

Meanwhile, if you don’t mind a few bugs and some Samsung default apps, the Watch4 and Watch4 Classic are the best options out there for Android users. But maybe wait for the software update.

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Write to Nicole Nguyen at nicole.nguyen@wsj.com