Hands on with the world’s thinnest smartphone

While Samsung and Apple are still (reportedly) preparing to launch their slimmest smartphones yet, the race has already begun.

Enter China’s Tecno, which brought the world’s thinnest smartphone (according to Tecno) to the Mobile World Congress (MWC) in Barcelona: the Spark Slim.

Albeit just a concept device, it worked like any regular Android phone.
Credit: Stan Schroeder / Mashable

Measuring just 5.75 millimeters (that’s if you don’t count the camera bump, of course), the Spark Slim feels like something you could use to cut tomatoes (in absence of knives and other cutting paraphernalia, of course). The display’s curvy edges accentuate the look even more, making the phone near invisible when seen from the side.

Despite being half as thin as a pencil, the Spark Slim actually packs some decent hardware, with a 6.78-inch AMOLED display, and a 5,200mAh battery. It also has some circular LEDs accentuating the cameras, which seems like overkill, but hey, why not? On the bottom, there’s a USB-C charging point, so you’re not actually losing much because of the phone’s extreme thinness.

Other specs are absent, which is no wonder given that the Tecno Spark Slim is a concept device at this point. I’ve spent just a small amount of time with it, but it seemed polished enough to me, so I wouldn’t be surprised if it actually did hit the market at some point.

Mashable’s on the ground at MWC 2025 covering the best tech products that have Barcelona abuzz.