Do you ever miss those times when bar or slate smartphones were ultra-thin and super-lightweight? While it makes me feel old (I certainly do), I miss the fact that brands back then were racing to build the slimmest and thinnest slates as possible. This stopped, of course, but it looks like we may soon see this trend once more with the Samsung Galaxy S25 Edge.
The Samsung Galaxy S25 Edge, which was recently released this week, could signal the return of ultra-thin smartphones. Featuring a remarkably slim 5.84mm profile, it is one of Samsung's thinnest to date. Alongside other models, it represents a resurging shift in 2025 toward thinner, lighter phones.
What!? Really?
Is the Samsung Galaxy S25 Edge leading a resurgence in the trend of ultra-slim smartphones?
For many of us in 2025, you might even question whether or not such devices actually existed. However, for the past few years, smartphone design trends have leaned toward larger batteries, stronger materials and improved durability, often resulting in thicker devices.
With the Galaxy S25 Edge, Samsung appears to be exploring a different balance: one that favours design and portability, while still delivering capable performance. The device sports a titanium frame, Gorilla Glass Ceramic 2 front, and a high-resolution 6.7-inch AMOLED display.
Inside, it runs on the Qualcomm Snapdragon 8 Elite for Galaxy, backed by 12GB of RAM. However, as with most ultra-thin designs, compromises are expected, such as a smaller battery and fewer rear cameras, compared to the Galaxy S25 Ultra.
Yes, really.
The vivo X5Max was once the world's thinnest smartphone
While this return to thinness may feel like a new direction, it's actually a revival of a trend last seen over a decade ago. Back in 2014, manufacturers competed to create the slimmest phone on the market, with the vivo X5Max leading the race at just 4.75mm thick.
At the time, it was a remarkable feat of engineering. But the era of ultra-thin smartphones quickly faded due to practical challenges and a certain Apple-infused scandal, but do read on to find out more.
Why ultra-thin smartphones fell out of favour
Ultra-thin smartphones may have looked sleek, but they often came with trade-offs that impacted daily use. Ultra-thin phones lacked the space for larger batteries, advanced camera modules, or robust cooling systems.
Many were structurally weaker, prone to bending when kept in back pockets or put under light pressure. These concerns became mainstream with incidents like the "bendgate" controversy involving the iPhone 6 Plus, which Unbox Therapy's Lewis Hilsentiger bent with just his bare hands. This shifted consumer demand toward stronger, more reliable builds.
As a result, smartphone makers moved toward a more balanced form factor, typically between 7mm and 9mm thick. This allowed for larger battery capacities, improved heat dissipation, better internal component layouts, and reinforced frames — all essential for modern flagship performance.
Why ultra-thin smartphones are trending again in 2025
New materials and new designs are allowing for the return of ultra-slim smartphones
In 2025, ultra-thin phones are making a comeback — this time with smarter design and better materials. Advances in chip efficiency, thermal management, and battery density have made it possible to create thinner devices without the compromises of the past.
First to the plate was the TECNO Spark Slim, which was featured at MWC 2025 as the World's Thinnest Smartphone (larger than 5.5-inches) at 5.75mm. Then there is the recently released Samsung Galaxy S25 Edge at 5.84mm. Next, we also have the Apple iPhone 17 Air, which is expected to arrive later this year. Let's take a closer look at the key devices leading this resurging trend.
Samsung Galaxy S25 Edge - Samsung's thinnest phone yet
The Galaxy S25 Edge is Samsung's answer to users who want a lighter, thinner flagship experience. Measuring just 5.84mm and weighing 163g, the phone blends portability with premium hardware. It's currently the only commercially available ultra-thin smartphone for this generation of ultra-thin slates.
While it lacks a dedicated telephoto or zoom lens and might have a smaller battery than the Galaxy S25 Ultra (8.2mm thick), the Galaxy S25 Edge is built for users who prioritise slimness without entirely giving up on flagship-grade hardware.
Here are the tech specs of the Samsung Galaxy S25 Edge:
- 6.7-inch QHD+ AMOLED display (3120 x 1440, 120Hz adaptive refresh rate)
- Snapdragon 8 Elite for Galaxy processor
- 12GB RAM, with 256GB or 512GB storage options
- 200MP main (OIS F1.7, 2x optical zoom) + 12MP ultra-wide (F2.2) dual rear cameras
- 12MP front (F2.2) camera
- measures 75.6 x 158.2 x 5.8mm, 163g
- 3900mAh battery, 25W wired charging, wireless charging support
- Titanium frame, IP68 rating, Android 15 with One UI 7
Pre-orders for the Samsung Galaxy S25 Edge start on 23 May 2025 in the US
TECNO Spark Slim – The world's thinnest 6-inch phone?
Unveiled as a concept device at MWC 2025, the TECNO Spark Slim measures only 5.75mm thin, yet it houses a surprisingly large 5200mAh battery. The phone also features a 6.78-inch 3D curved AMOLED display and a dual 50MP rear camera setup.
Although it's not yet commercially available, the Spark Slim demonstrates how brands can integrate larger batteries and capable hardware into ultra-thin bodies — something that was difficult a decade ago.
Yep, you can't buy the TECNO Spark Slim just yet, it's still a concept phone
Apple iPhone 17 Air – Apple’s thinnest iPhone yet?
Apple is also expected to join the thin smartphone race with the iPhone 17 Air, set to launch around September 2025. Rumours suggest a 5.44mm body, a 6.7-inch OLED display, and a single 48MP rear camera, powered by the upcoming Apple A19 chip.
If the leaks are accurate, the iPhone 17 Air could become the thinnest iPhone ever released, catering to users who want an ultra-light Apple device with premium materials and performance.
Bonus - What is actually the world's thinnest smartphone?
Truth be told, all of the smartphones mentioned above are not the thinnest by far. Not even the vivo X5Max (4.75mm). This record is actually held by foldable smartphones like the Huawei Mate XT Ultimate, which is 3.6mm thin at its thinnest point when it is unfolded.
All of the ultra-thin slate smartphones mentioned above, aside from the Huawei Mate XT Ultimate, are not foldable devices. We fully expect foldable display devices to become even thinner.
Conclusion - Thinner, stronger and… more expensive?
If you've noticed by now, titanium was quite frequently mentioned in the tech specs and features listed above. For those who don't know, titanium is a metal that is both super light and very strong. 100 grams of titanium would cost about $138 to $240 (~RM1017) alone.
Other materials, like the stronger and thinner Gorilla Glass Ceramic, would be equally expensive. When factored in with the latest tech specs and other features, we're not surprised at the $1099 (~RM4750) price tag that the Samsung Galaxy S25 Edge is going for. Therefore, until engineers find more affordable and stronger materials (like graphene), ultra-thin smartphones will likely be fairly expensive to buy.
Would you buy an ultra-thin smartphone?
However, considering that there are still plenty of buyers for foldable display devices priced upwards of RM10K, upcoming ultra-thin devices are not so expensive that they can't be bought by many people. At least it gives another option for people with money who don't like thick and heavy smartphones.
Given the above, are we seeing the true comeback of ultra-thin slate smartphones? With Samsung, TECNO, and Apple all moving toward slimmer designs, 2025 might mark a turning point where thinness is no longer just about style, but also backed by real improvements in tech.
Would you pick a thinner slate smartphone like the Galaxy S25 Edge or the iPhone 17 Air for everyday use? Or do you prefer thicker phones with larger batteries and more camera features? Share your thoughts in the comments below, but if you do buy an ultra-slim smartphone, we hope you won't put it in your jeans back pocket at least. In the meantime, stay tuned to TechNave.com for more updates.
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