The buzz around slim phones is back. Samsung teased a slim design at their January Galaxy Unpacked event, and Apple is rumored to be developing the iPhone 17 Air. But Tecno is stealing the spotlight with the Spark Slim, a phone that truly embraces the “slim” moniker without sacrificing battery life or key features. This device boasts a 5,200mAh+ battery, a sub-6mm thickness, and a dual-camera system, setting a new standard for what a slim phone can be.
Announced just days before Mobile World Congress 2025, the Tecno Spark Slim is being touted as the “world’s thinnest smartphone.” Having had hands-on experience with a working prototype, I believe this device offers a compelling glimpse into the future of slim phones, and sets a benchmark for devices like the rumored Galaxy S25 Edge and iPhone 17 Air.
A Battery that Outperforms the Galaxy S25 Ultra
Tecno Spark Slim
Rumors suggest that both Apple and Samsung might compromise on battery capacity for their upcoming slim phones. The Samsung Galaxy S25 Ultra packs a 5,000mAh battery, and the anticipated Galaxy S25 Edge is expected to have even less. In contrast, the Tecno Spark Slim boasts a 5,200mAh battery, surpassing even mainstream flagship smartphones. Achieving this capacity in a form factor slimmer than anything currently available is a significant feat, promising all-day battery life.
Tecno Spark Slim and iPhone 16 Pro side by side.
The Tecno Spark Slim measures an astonishing 5.75mm thin. Compare that to the Samsung Galaxy S25 at 7.2mm, the Galaxy S25 Ultra at 8.25mm, the iPhone 16 at 7.8mm, and the iPhone 16 Pro Max at 8.25mm. Even the rumored Galaxy S25 Edge, at approximately 6mm, is thicker. Remarkably, the Spark Slim achieves this thinness without sacrificing fast charging, offering the same 45W charging speed as the Galaxy S25 Ultra. Integrating such a large battery with fast charging capabilities into a 5.75mm form factor is a testament to Tecno’s engineering prowess.
The Tecno Spark Slim: A Comprehensive Slim Phone Experience
Tecno Spark Slim display
My hands-on experience with the Spark Slim left a positive impression. The 6.78-inch AMOLED display with curved edges contributes to a comfortable in-hand feel, reminiscent of earlier slim phones, but with significant advancements in display size, sharpness, and overall quality. Unlike the flat sides of the rumored Galaxy S25 Edge, the Spark Slim’s curved edges enhance the perception of thinness. Even in bright indoor lighting, the screen remained easily readable, promising a peak brightness of 4,500 nits on supported content. The 144Hz refresh rate ensures smooth scrolling and a responsive user interface. A 13MP selfie camera is also integrated into the sleek design.
Tecno Spark Slim screen
Tecno has remained tight-lipped about the specific chipset powering the Spark Slim, only revealing that it’s an octa-core processor. It remains to be seen how the device will manage heat dissipation, especially if a flagship-level processor is incorporated into this slim design. However, confirmed support for Google Gemini adds to the device’s appeal.
The Tecno Spark Slim features a dual rear camera setup, with both lenses boasting 50 megapixels for sharp image capture. While the camera performance may not rival flagship offerings from Samsung or Apple, the inclusion of a dual-camera system is noteworthy, especially given the rumors of a single rear camera on the iPhone 17 Air.
While the Tecno Spark Slim shows immense promise, it’s important to remember that it’s still in the prototype stage. A staggered launch is anticipated, but no official release date has been announced. If this device delivers on its potential, it represents a significant step forward for slim phones, demonstrating that thinness doesn’t have to come at the cost of screen quality, battery life, or essential features.
