The world has always been fascinated with the smallest, the lightest, the fastest, and now, more than ever, brands are pushing the limits. Entering the fray are Tecno’s Spark Slim and Samsung’s Galaxy S25 Edge, two devices that push the envelope on ultra-thin designs without, apparently, compromising on capabilities. The devices that were announced at MWC 2025 and Galaxy Unpacked 2025, respectively, offers a different vision of what a thin flagship should look like. Let’s break it down.
Tecno Spark Slim: The Best of Both Worlds: A Slim Smartphone with Outstanding Battery Life
From a design standpoint, Tecno took an aggressive approach with the Spark Slim model by achieving a shockingly thin 5.75mm body, a record thinness for ultra-slim devices. But here’s the thing: it still has a huge 5,200mAh battery. Yes, some thin phones look good but have poor battery life, which is something that Tecno is attempting to change. However, this phone isn’t just a battery monster, the 6.78-inch 3D curved AMOLED display offers a 1.5K resolution (1224p) and a smooth 144Hz refresh rate, which means that scrolling and gaming will be an absolute delight. The screen also gets very bright up to 4,500 nits – direct sunlight will not reflect off the screen.

For cameras, Tecno has included 50MP dual rear cameras and a 13MP front-facing shooter. While not quite flagship-level these days, for a device in this segment, it’s more than respectable. The stainless steel unibody and recycled aluminium build make it feel more premium than its likely price tag would suggest. Tecno has not yet disclosed the exact chipset, but it has revealed that the chip set is an octa-core chip that is efficient and delivers smooth performance. In other words, it’s very thin, fairly powerful, and has a great battery life. If Tecno manages to price this device correctly, it could be a real game changer.
Samsung Galaxy S25 Edge: Elegant and Sophisticated, Yet Quite Conservative.
The Galaxy S25 Edge from Samsung is the company’s take on the growing trend of slim smartphones, and it is 6.4mm thick – not as thin as the Spark Slim, but thinner than most Galaxy S series flagship smartphones. Samsung isn’t only attempting to make the phone as thin as possible. It’s about finding the perfect harmony between style and capability. The 6.7-inch OLED display comes with a 120Hz refresh rate, and while the Spark Slim has better brightness, you can expect colours and black levels to be top-notch on the Samsung. As for the specifications, it’s as premium as it gets. But the real star here is the camera system. Megapixels are still the currency of camera phones, and 200MP is how Samsung is marketing its new main sensor. 12MP front-facing camera – not great, but you know Samsung will be able to make it look decent with its software. The problem is that slim design comes with a 3,900mAh battery – not the best, but definitely not the worst. Samsung is hoping that 25W fast charging and wireless charging will help, but the battery life might be a concern for heavy users.

Thin vs. Thinner: Which One Is Better?
It’s clear both brands are taking wildly different approaches to ultra-thin smartphones: The Tecno Spark Slim focuses on the battery and display technologies while keeping the weight and environmental friendliness of the device at an acceptable level. Samsung Galaxy S25 Edge: Offers a good balance of thickness, performance, and top-end camera specifications, but the battery life is not the best. In the end, what Tecno is doing is saying that you don’t have to sacrifice battery life to make a ridiculously thin phone. On the other hand, Samsung offers high-quality specifications but the small battery pack might be an issue for some users.
Now, the real question: Which one would you pick?