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The Onyx Boox Tab Ultra C is an impressively constructed jack of all trades, offering a large, colourful canvas for reading alongside a sharp note-taking facility. However, for web browsing, media playback, and pretty much any other function, you’re still better off with a regular smart device or laptop.


  • Premium build
  • Access to Google Play Store
  • Solid stylus experience


  • Limited for web and media content
  • Big and bulky
  • Expensive

Key Features

  • Colour e-ink displayCombines the easy-reading, power-saving benefits of e-ink with a 4,096-colour palette
  • Runs on Android 11The device comes preinstalled with Android 11
  • Bundled with a stylusComes with a full-sized stylus capable of 4,096 levels of pressure


Some would argue that the e-reader arguably reached its final form some time ago, whenever it was that Amazon started offering Kindles that were as nice-to-hold as they were sharp-to-read. Onyx clearly believes otherwise.

Previous efforts from the firm, like the Onyx Boox Note Air 2 Plus or indeed the Onyx Boox Tab Ultra (no ‘C’), combined the E Ink readability and sterling battery life of an e-reader with the huge display, sophisticated software, and wider app access of an Android tablet. They also included note-taking capabilities via a bundled stylus.

The Onyx Boox Tab Ultra C takes that formula and goes one step further, adding a splash of colour to proceedings. At a cost of £600 on Amazon, this certainly isn’t a cheap digital reading and note-taking solution. So is that extra expenditure worth it?


  • Solid metal build
  • At 480g, quite heavy for an e-reader
  • Bundled stylus and magnetised edges

Previous Onyx e-readers have been impeccably built, and that remains the case with the Boox Tab Ultra C. This blocky, squared-off tablet has a solid metal body that screams ‘premium’ – at least within the context of a tablet.

In e-reader terms, the Boox Tab Ultra C is somewhat unforgiving. Those hard, squared-off surfaces aren’t the most comfortable to hold for long periods.

While one side-bezel is around three times the thickness as the rest, suggesting you should be holding onto it with one hand, an overall weight of 480g (twice the weight of even the heaviest smartphone) means that you’ll want to bring a second hand into play, or to prop this tablet up on your lap. The optional keyboard cover will prop it up on a flat surface for you, at the expense of adding further weight.

Onyx Boox Tab Ultra C in-handOnyx Boox Tab Ultra C with stylus on a wooden desk.
Image Credit (Trusted Reviews)

I briefly tested that keyboard case, and found it to be a well-built accessory that provides premium protection along with a somewhat unnecessary typing provision. The typing experience is solid, with good key travel, if slightly too firmly sprung. However, it’s absolutely no replacement for even a mediocre compact laptop. It’s more cramped, less viable for actually typing on your lap, and the sluggish display isn’t exactly conducive to the sort of light multitasking and app-switching that most writing projects require.

Further tablet influences can be seen on the back of the Boox Tab Ultra C with its 16MP camera. This is being positioned as a ‘smart scanner’, which is a reference to its intended function as a document scanner rather than for snapping pictures of your dog.

There’s a patterned plastic strip running up the back of the entire thicker side, which offers a warmer, softer texture for your fingers to grip, as well as a likely portal for the device’s Wi-Fi connectivity. Both of the longer edges have magnetised sections towards the centre where the included stylus can be affixed, though you have to make some effort to get the alignment right. It’s not quite the effortless snap that I would have liked.

Rear of the Onyx Boox Tab Ultra COnyx Boox Tab Ultra C tablet leaning against books on a desk.
Image Credit (Trusted Reviews)

USB-C is in the headlines right now thanks to Apple’s Pauline conversion with the new iPhone 15 line, but it’s been an everyday fact of life for everyone else. There’s a USB-C port provided here, though somewhat curiously, it’s situated on the far left of the bottom edge. Not that such odd placement really matters, given the typically epic battery life figures that such e-readers achieve.

On the top edge of the Ultra C you’ll find an elongated power button, which also doubles as a fingerprint sensor. That’s an unusual inclusion for a pure e-reader, and nods to the device’s hybrid nature. You’ll need to dive into the Settings menu to activate this, though, as it doesn’t form part of the set-up process.


  • 10.3-inch E Ink screen
  • 4,096 colours
  • Front lit

Onyx has equipped the Boox Tab Ultra C with a 10.3-inch Kaleido 3 E Ink display, with a maximum resolution of 2,480 x 1,860 (300ppi) in black and white. It’s plenty big and sharp enough for all book content, and it also sports strong frontlighting with fully adjustable brightness and warmth.

However, the big feature here is the Boox Tab Ultra C’s colour output. Don’t go expecting a tablet-like experience – at just 4,096 colours, this offers a very basic, washed-out palette, while colour content also halves the screen resolution to 1,240 x 930 (150ppi). Still, it makes reading comics on the device a much better experience than on regular e-readers.

You can technically watch YouTube videos on this tablet, but you really wouldn’t want to. The poor contrast, limited colour palette, and glacial refresh rate can make for a bizarre, almost impressionistic experience.

Onyx Boox Tab Ultra C on a tableOnyx Boox Tab Ultra C displaying a comic page on desk.
Image Credit (Trusted Reviews)

The screen also suffers badly from ghosting throughout. You’ll often encounter the faint suggestion of an app icon or some other screen element that has been displayed previously.

Onyx has implemented an app optimisation system, which lets you change the balance of sharpness and speed according to the content. It’s on Balanced by default, but HD achieves sharper text, Fast Mode gets you better (but still clunky) web browsing, and Ultrafast is technically for video playback. Again, though, you really don’t want to be relying on the Onyx Boox Tab Ultra C for such things.

While it’s good that the manufacturer has thought about the limitations of this screen technology, and how to mitigate those issues for a variety of content, it’s all a bit clunky. Do you really want to be fiddling about in a dedicated menu every time you switch to a new kind of media content? For most casual e-reader users, I suspect that the answer is ‘no’.

Onyx Boox Tab Ultra C on a tableOnyx Boox Tab Ultra C with handwritten note test displayed.
Image Credit (Trusted Reviews)

It might be laggy when it comes to fast-moving media content, but the screen responds well to the bundled stylus. With 4,096 pressure levels and a size and feel that can only be described as ‘pen-like’, jotting down notes feels natural and reliable.

Make no mistake here – while the Onyx Boox Tab Ultra C might be positioned as a colour E Ink device, this isn’t a ‘best of both worlds’ device by any means. Indeed, I’d argue that the whole colour element is overplayed at best, and superfluous at worst.

It does its best work with e-books and basic note-taking – just like the Kobo Elipsa 2E, the Kindle Scribe, and the ReMarkable 2, all of which use monochrome E Ink displays for a significantly lower price.

Performance and software

  • Snapdragon 662 SoC
  • Sparse UI based on Android 11
  • Access to Google Play Store

The Onyx Boox Tab Ultra C runs on a Snapdragon 662 chip with 4GB of RAM backing it up. If that makes it sound rather like an Android tablet, that’s because it essentially is one.

True, it’s only running on creaky old Android 11 (Android 14 is imminent in the world of smartphones and tablets), and a heavily simplified version of it at that. But the home screen here looks a bit like a Classic Mac OS/Windows 95-style demake of Google’s mobile operating system. We’re talking clean, basic app icons sat on top of a blank background, with larger folders for any downloaded books or created notes. It works well here.

There’s an Android-style navigation bar along the bottom for books, home, files, and settings, and you get a bunch of pre-installed apps and tools just like any other Android device. There’s a bespoke web browser, a dictionary, several basic tools, and more.

Crucially, there’s also the Google Play Store. This means that you have access to all of the thousands of apps that have built up on Google’s app store over the past decade-and-a-half. Most of these will be wholly unsuited to use on this device, but the main benefit is that you’ll be able to access any ebooks you’ve accumulated across multiple services and cloud storage apps over the years.

Onyx Boox Tab Ultra C on a table next to booksOnyx Boox Tab Ultra C displaying an ebook with a stylus.
Image Credit (Trusted Reviews)

Within minutes, I was downloading the ebooks and digital comic books I had bought over the years from the Amazon Kindle app and Google’s own Play Books app, and reading and annotating documents stored on Dropbox or OneDrive. Reading all of these formats in their respective apps, or through the prominent Library folder in the case of downloaded PDFs, felt completely natural on the Ultra C’s E Ink display. Native, even.

It’s important to keep expectations in check, however. The Onyx Boox Tab Ultra C might be built like an Android tablet, but it doesn’t perform like one. Whether it’s that lowly Qualcomm chip or the sluggish E Ink display – I suspect a bit of both, but predominantly the latter – most tasks beyond simply skimming through a text file take several beats or more longer than you might be accustomed to on your tablet or phone.

Classic Android system tasks like logging into an app, moving between menus, or opening a web page feel a lot more laborious here. Again, this is all quite fast for an e-reader, but when you start treading on the toes of tablets (Onyx itself calls this an “ePaper tablet PC”), you should expect to be held to a higher standard.

It’s not quite as intuitive a UI as it could be, either. You’ll need to dive into the Settings menu to set up some things that you might consider fundamental in a more regular Android device, including a Wi-Fi connection and a password.

Meanwhile, I found the optional gesture-based navigation system to be somewhat convoluted. You swipe up from the left edge for multitasking/app switching, up from the middle for home, and from the right for the E Ink Centre, which lets you tweak those display settings according to the task. Sliding up and down on the right of the screen, meanwhile, adjusts brightness.

Rear of the Onyx Boox Tab Ultra C leaning against a wallOnyx Boox Tab Ultra C tablet with stylus leaning against a wall.
Image Credit (Trusted Reviews)

There’s also the option to swipe in from the left to go back, which I’d recommend you activate. The option to swipe up and down on the left for volume control on any video or audio content feels a bit odd, at least within a tablet context.

I can’t fault the note-taking software, however. As well as a rock-solid writing experience with the stylus, the in-built Notes app is intuitive and sufficiently capable. Scrawl away on one of the document templates, then hit the AI button, and the Tab Ultra C will (after a lengthy pause) translate it into digital text. The handwriting recognition seems to be pretty faultless, and it supports an impressive 66 languages.

Document scanning using the appropriately titled Scan Documents app works efficiently too, and of course, the combination of scanned PDFs and solid handwriting opens up the potential for easy document signing and sharing.

Onyx has packed its tablet with a 6,300mAh battery, which wouldn’t be especially large for a 10-inch tablet with a power-hungry LCD, but is absolutely huge for a low-power E Ink display.

Sure enough, battery life is right up there in large e-reader territory. That is, I didn’t need to charge it once during my week or so with the device, barely draining half the tank. While cranking up that frontlighting will obviously sap energy faster, the nature of E Ink means it’s unnecessary with any kind of reasonable ambient lighting in play.

Standby time is superb, with the Ultra C losing only around 1% a day when not in use.

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Should you buy it?

You want a splash of colour with your ebooks

The Onyx Boox Tab Ultra C serves as a decent full-sized e-reader with an E Ink display that’s easy on the eye, but it also adds a dose of colour, making it viable for digital comics and illustrated books.

You want a full-fat tablet experience

The Onyx Boox Tab Ultra C might have a colour display and run on Android, but its performance and refresh rate are way short of even the cheapest Android tablet when it comes to web browsing and media consumption.

Final Thoughts

The Onyx Boox Tab Ultra C is an interesting showcase of what’s possible within the traditional e-reader space, offering a large colour E Ink canvas for your books and comics and Google Play Connectivity. As a pure e-reader, it’s a very strong provision, provided you can live with the weight.

It’s also a very good note-taking device, with a responsive stylus bundled in and some simple but powerful software for jotting down notes and sketches. The built-in scanning function furthers its document mastery.

However, it’s far from the all-encompassing hybrid that you may be hoping for. While it can surf the web and play video content, inherent limitations with E Ink technology mean that you wouldn’t necessarily want to. It also costs a lot more than the premium e-reader-notebook competition.

It’s another eye-catching hybrid device from Onyx, but the Book Tab Ultra C has us wondering whether this is the true way forward for e-readers, or just another attractive dead-end.

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We test every e-reader we review thoroughly. We use the device over the review period. We’ll always tell you what we find and we never, ever, accept money to review a product.

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How long does the Onyx Boox Tab Ultra C last?

Thanks to an E Ink display and large battery, the Onyx Boox Tab Ultra C can last for days if not weeks depending on usage, and only sips 1% a day in standby mode.

Full specs

Onyx Boox Tab Ultra C review

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