Luna Smart Ring Gen 2 review: this Oura ring alternative has great battery life and sleep analytics

I haven’t had the best experience with the best smart rings. The first one I tried barely held its charge and didn’t sync well to its app so half of my metrics weren’t actually tracked. So, I was initially hesitant to try another smart ring, but I’m so glad I gave the Luna Smart Ring Gen 2 a try.

Announced at IFA 2025, the Luna Smart Ring Gen 2 is the second generation that tracks your biomarkers, and helps you understand and improve them. What intrigued me the most about the Luna Smart Ring Gen 2 was its sleep and fertility tracking features, as it’s rare to find a wearable device that caters specifically to women.

I wore the Luna Smart Ring Gen 2 for over a month to see how well it performed and if it would help me kickstart my 2026 fitness and wellness journey – here’s how it went.

Luna Smart Ring Gen 2 review: price and availability

The Luna Smart Ring Gen 2 launched in mid-2025 and is priced at £299 / $329. It comes in five colours, including midnight black, lunar black, stardust silver, rose gold and sunlit gold.

To use the Luna Smart Ring Gen 2, you need to download the Luna Ring which is free and doesn’t come with a subscription fee.

Luna Smart Ring Gen 2 review: unboxing and set-up

The Luna Smart Ring Gen 2 arrived in a petite box, and comes with the ring, charging cable and Surge Charger which looks like a fancy ring box which matches the colour of the ring. To set it up, I fully charged the ring box with the ring inside which took up to 120 minutes, before downloading the Luna app.

In the app, I signed up for an account and connected the smart ring via Bluetooth. From there, I had to fill out some personal details, including my age, gender, height and weight. To understand me better, the app asked questions about what I wanted to get out of my Luna Smart Ring Gen 2 experience. I selected everything it listed, including sleep, activity, nutrition, wellbeing and fertility.

Once I’d added all my answers, the app had a very quick firmware update and then it was good to go. Aside from the charging, the app set-up process took under five minutes.

Luna Smart Ring Gen 2 review: design and features

The main advancements from the first to the second generation of the Luna Smart Ring is a slimmer design, upgraded hardware, an accompanying charging case and a new Luna AI coach within the app – so let’s get into its design and features.

Once it’s charged, the Luna Smart Ring Gen 2 has between four - seven days of battery life, and the Surge Charger box holds up to 30 days worth of charge, so you can keep your ring topped up via the box. I found the battery life to be extremely impressive, and really enjoyed having the additional Surge Charger for quick top-ups.

The design of the Luna Smart Ring Gen 2 is pretty simple, and it has a width of 8mm and thickness of 2.9mm. It weighs between three - five grams depending on the ring size and is made from titanium. It has a subtle diagonal stripe design on the front but is otherwise plain. It’s quite chunky for smaller fingers, but it sits comfortably and doesn’t easily knock or get stuck on things.

Like most smart rings, the Luna Smart Ring Gen 2 tracks multiple health, fitness and wellness metrics, including sleep, activity, stress, calories, recovery and more. On the inside of the ring are its sensors, including an optical heart rate sensor, blood oxygen sensor, PPG sensor and skin temperature sensor.

The heart rate and blood oxygen sensors flash different colours periodically when they’re measuring. The former lights up with green LEDs while the former flashes a red light. The Luna Smart Ring Gen 2 is also water resistant of up to 50 metres, so it can handle handwashing or rain but should steer clear of a swimming pool.

A few of its key tracking features include sleep stages, period tracking, daily efforts and stress. For sleep, the Luna Smart Ring Gen 2 breaks down your sleep stages, tracks your sleep quantity, and makes suggestions for each night. Period tracking is slightly more manual with you having to input your symptoms, but it keeps track of your entire cycle and its different phases to help you keep track of your fertility.

Other details it tracks and shows is stress and activity levels, including your heart rate, step count, skin temperature, SpO2 and more. The app now comes with Luna AI, which gives you personalised wellness advice. Users can also ask it questions about specific concerns or metrics and Luna AI helps you understand it better.

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Luna Smart Ring Gen 2 review: performance and app

I started wearing the Luna Smart Ring Gen 2 at the beginning of December but used it more during January after setting myself some strict health-focused New Year’s resolutions. I’ve been testing the Luna Smart Ring Gen 2 for over a month now, and I’ve not had to worry about charge at all, which has always been one of my main concerns with smart rings.

During my testing, the Luna Smart Ring Gen 2 held its charge for up to a week if not more on the first time I started wearing it. The charge has stayed consistent throughout the month and a half I’ve been testing the Luna Smart Ring Gen 2, and the Surge Charger has been impressive, too. I’ve only had to recharge the Surge Charger once since testing, so I’ve found the battery life of the Luna Smart Ring Gen 2 to be very strong.

I found the Luna Smart Ring Gen 2 to be comfortable to wear, although it’s quite thick and chunky. My fingers are quite small so it does take up a fair bit of space, but it’s not uncomfortable or distracting. The sensors on the inside flash quite brightly at night which could be a bit intrusive at times, but in general, I hardly noticed them.

Moving on to what the Luna Smart Ring Gen 2 actually tracks – that’s where it really shines, after all. In the app, I started by adding in a few areas I wanted to track, including fertility and daily goals. For fertility, I added the duration and date of my last period and contraception details, and for daily goals, I customised my water intake and step count.

I found the Luna app easy to use and set up, and once my details and customisations were added, the Luna Smart Ring Gen 2 logged and saved everything so I didn’t have to continuously update things. It syncs to the ring well and quickly, and I found it to be very responsive for certain activities, like running, walking and napping.

There are some areas where you’ll have to manually add things into the app, like food, drink, water intake, period symptoms and sleep if you didn’t wear the Luna Smart Ring Gen 2 to bed. It didn’t always detect certain workouts – although it did recognise that my heart rate was higher – so I had to add HIIT or yoga workouts into the app directly. This didn’t really bother me, but it’s worth noting.

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The sleep tracking was my favourite part of the Luna Smart Ring Gen 2. I love my sleep and I was surprised to see the different stages of sleep I went through each night. The Luna Smart Ring Gen 2 also tracked its duration, quality and measured everything to show what I should improve on which I found very useful.

I had a very positive experience with the Luna Smart Ring Gen 2 and its app, although I rarely used the Luna AI coach. The only times I used it was to ask a question about a metric that I didn’t understand, but I didn’t find it completely necessary as the app is so helpful. I didn’t find the insights to be any better than what the app was already providing.

Luna Smart Ring Gen 2 review: verdict

The Luna Smart Ring Gen 2 gets high marks from me and I definitely will be continuing to use it to help improve my health and fitness journey. Women will definitely love this smart ring as it has valuable insights into fertility and period tracking, but everyone can enjoy using the Luna Smart Ring Gen 2 as it comes with so many helpful insights and tracking information.

The app is subscription fee, responsive and extremely insightful, despite the Luna AI coach not doing that much for me. The sleep features are definitely the best part of the ring and app, but it keeps track of all types of activities and health information that you could want to track.

The Luna Smart Ring Gen 2 is nice to wear and the charging is the best I’ve tried so it’s really hard not to like it! I couldn’t think of many negatives, and it’s not badly priced either – plus the lack of an ongoing subscription makes things that bit sweeter, too.

Luna Smart Ring Gen 2 review: alternatives to consider

The Oura Ring Gen 4 is the best smart ring we’ve tried, and it sits at the top of our best smart ring guide for good reason. If you don’t mind spending a bit more, the Oura Ring Gen 4 is a great choice, but the Luna Smart Ring Gen 2 is a great cheaper alternative.

If it’s sleep tracking you’re after, the Ultrahuman Ring Air has some of the best sleep tracking features around. It looks at eight different metrics and has a Circadian Phase Alignment insight which our reviewer found to be very insightful. It also comes with no subscription fees.