Exploring the Limits of Smartphone Thinness
How thin can a smartphone really get?
In the race for the slimmest smartphone, Samsung has announced that its upcoming Galaxy S25 Edge will boast a thickness of just 6.4mm, setting a new record for the company’s lineup in 2025.
However, Tecno, a Chinese company, has taken thinness to the next level with the introduction of the Spark Slim, measuring an astonishing 5.75mm. This groundbreaking achievement has earned the Spark Slim the title of the world’s thinnest phone to date.
Having had the opportunity to experience the Spark Slim firsthand at MWC 2025 in Barcelona, I can attest to its remarkable engineering. Holding the device feels like a glimpse into the future of smartphone design.
Image credit: Anyron Copeman / Foundry
Despite its impressive design, Tecno has clarified that the Spark Slim is purely a concept and has no plans for commercial release, even in China.
There are notable concerns with such an ultra-slim device, including issues of durability and overheating. The thin profile of the Spark Slim may compromise its durability, leading to concerns about its ability to withstand accidental drops or pressure. Additionally, the compact design leaves little room for proper heat dissipation, potentially resulting in overheating during intensive usage or charging.
While there are challenges associated with ultra-thin smartphones, Tecno’s innovation with the Spark Slim showcases the possibilities for future advancements in smartphone design. By pushing the boundaries of slimness, Tecno has earned recognition in Tech Advisor’s Best of MWC 2025 Awards.
