When it comes to CES announcements, smart locks don’t often move the needle. Though how you lock your doors might not top the list of technological advancements, Aqara’s newest smart lock just might be the next practical and necessary home upgrade.
The Smart Lock U400 is one of the first UWB-enabled locks available for consumers. It pairs seamlessly with the home key function in Apple Wallet, allowing you to unlock your home just by walking up to the door. This efficiency will save you time, so there’s no fumbling with keys while your hands are full. This is because the U400’s UWB (ultra-wideband) connection is more accurate, more secure, and smarter than most other smart locks out there.
What is UWB, and why would you want it in a smart lock?
- Brand
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Aqara
- Connectivity
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UWB, Bluetooth
- Integrations
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Home key in Apple Wallet, Aliro-enabled for Android
- Compatible Locks
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Standard US 60/70mm deadbolt
- Battery
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1-2x rechargeable Li-ion battery
- Keypad
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Yes
The Aqara Smart Lock U400 is one of the first smart locks to utilize UWB (ultra-wideband) radio and Bluetooth connections for a smarter, more secure solution that won’t accidentally unlock and is more resistant to rally attacks than most of its competition. The U400 works with Home Key in the Apple Wallet and is Aliro-ready for Android devices.
UWB is an ultra-wideband connection that uses low energy for short-range, high-bandwidth communications over a broad range of the radio spectrum. This technology has traditionally been used in radar imaging, but can also be used for sensor data collection, precision location, and tracking.
Previously, UWB technology was limited to the smartphone and automotive markets, as UWB provides more accurate location tracking and data for everything from parking sensors to AirTags. But UWB can be used for more than just tracking where your phone or car happens to be at any given time.
Aqara’s Smart Lock U400 uses ultra-wideband radio waves for spatial intelligence, allowing your phone to unlock the door through proximity, while UWB’s Time of Flight (ToF), Angle of Arrival (AoA), and Scrambled Timestamp Sequence (STS) features make the U400 smarter and more secure than your average smart lock.
Most smart locks currently on the market still need to use Wi-Fi or Bluetooth to connect the lock to your phone, and require manual input of either a PIN or biometrics to unlock your door, or set up auto-lock features. The U400 is designed to be seamless, simply locking or unlocking when you walk toward the door with your phone or smartwatch on hand. No need to use a fingerprint, eye-scan, or PIN for entry.
A UWB-enabled smart lock is convenient for anyone who’s ever struggled to get in the door while carrying heavy grocery bags or wrangling children or pets. But it’s also a great choice for those with greater accessibility needs. Since a UWB lock doesn’t require a manual input for either a code or biometrics, it offers hands-free entry – at least as far as your door’s locking mechanism goes. The door itself is another matter, but unlocking your door hands-free is a major quality of life upgrade.
Aqara Smart Lock U400: Key features
Courtesy of its UWB capabilities, the Aqara Smart Lock U400 has quite a few handy features. Since it was designed to work with Home Key in the Apple Wallet, you can use your iPhone or Apple Watch as a key to your front door.
With UWB’s directional awareness combined with Bluetooth for precision presence detection, the U400 will only unlock the door when approached from outside, so you won’t be randomly unlocking your door when you walk past it on the inside.
The U400 also boasts NFC credentials and works with voice assistants. It can use fingerprint biometrics or a PIN for access, and even features a mechanical lock. So, it’s a full smart lock system that integrates UWB auto-unlock to provide various access options for your home. And it works with standard US deadbolts for easy DIY installation, no contractors necessary.
It makes use of Unlock on Approach or Tap-to-Unlock with Apple Wallet to gain access, and automatically syncs to your Apple Wallet and shares keys with your household.
In addition, the U400 was built on Thread and has a Matter certification, meaning it doesn’t need a proprietary control hub and will integrate seamlessly with the smart home tech you already have. So, if you have smart outlets, plugs, a speaker system, lights, or even climate control systems, you can integrate the Aqara Smart Lock U400 into your home without issues.
Along with its Matter certification, the U400 is Aliro-ready for future universal digital key support access across smartphone and wearable platforms. Aliro is expected to launch in early 2026, which will allow the U400 to sync with Android phones and wearable devices in addition to iPhones and Apple Watches within weeks of the lock’s release.
Smarter, more secure than the competition
Essentially, Aqara’s mission is that a space should adapt to its inhabitants. This is why the U400 lock doesn’t require manual user input, but rather senses the presence of a connected smartphone to lock or unlock the door.
With UWB’s Time of Flight (ToF), Angle of Arrival (AoA), and Scrambled Timestamp Sequence (STS) capabilities, the Aqara Smart Lock U400 is resistant to relay attacks and more secure than Bluetooth-only smart locks. Aqara also added IEEE 802.15.4z Scrambled Timestamp Sequences for additional anti-relay protection.
Angle of Arrival also means the U400 is capable of detecting directional context and will keep your smart lock from accidentally unlocking the door when you pass by from the inside or happen to be on your front lawn. Bluetooth or Wi-Fi-enabled smart locks lack this kind of precision directional context, which can lead to accidental unlocks when you simply wander too close to your door while cleaning or doing yard work.
As for locking your door, the U400’s auto-lock feature is powered by a built-in gyroscope, not just a timer. So, it’s a more secure auto-lock than many of its competitors, which use a timer to automatically re-lock the door.
A true game-changer
Upgrading small items around your home for modern features and conveniences can often change the way you use your living space, and the Aqara Smart Lock U400 is one of those key products.
While other smart locks can definitely improve your home security and offer easier access for frequent visitors, like dog walkers or babysitters, they don’t completely reinvent the wheel when it comes to locking and unlocking your home door on a daily basis. The U400, on the other hand, provides a more seamless hands-free entry process. And that’s the kind of modern convenience you can really use.
You also don’t need to stop in your driveway to ensure your phone doesn’t accidentally unlock your front door when on your way out or dig into your bag to grab a clunky set of keys before getting out of the car on your way home. While these aren’t the worst problems to have, they are problems that can be solved with a simple DIY home upgrade.
As for security concerns, thanks to the Aqara Smart Lock U400’s ultra-wideband radio connection, the U400 is one of the most secure smart locks yet. Between all the additional UWB features and built-in gyroscope, the U400 ensures a better, faster auto-lock compared to timer-only solutions. Plus, it’s resistant to relay attacks compared to Bluetooth-only smart locks.
Aqara’s U400 is compatible with Apple devices. It is Aliro-ready, so it will work with Android devices, as Aliro is expected to launch in the first quarter of 2026. So, the U400 should be compatible with Android devices by March 2026, if not earlier.
