The Return of Thin and Light: Ultrathin Smartphones Sweep the Market Again

The Return of Thin and Light: Ultrathin Smartphones Sweep the Market AgainA decade ago, the mobile phone industry was swept by a "thin and light" craze. OPPO R5 (4

The Return of Thin and Light: Ultrathin Smartphones Sweep the Market Again

A decade ago, the mobile phone industry was swept by a "thin and light" craze. OPPO R5 (4.85mm thick) and vivo X5Max (4.75mm thick) became iconic examples of this design philosophy, with the vivo X5Max still holding the record for the thinnest phone ever made. However, manufacturers subsequently shifted their focus to "stacking specs," prioritizing performance, imaging capabilities, and battery capacity, causing the pursuit of thinness to fade into the background. Today, phones under 7.5mm thick are mostly mid-range models, while flagship phones generally exceed 8mm. But, like a recurring fashion trend, the "thin and light" concept is making a powerful comeback in 2025, with numerous manufacturers launching or planning to launch ultrathin new phones, igniting a new wave of competition. Samsung's Galaxy S25 Edge is poised for release, rumors swirl around the Apple iPhone 17 Air, Transsion's Tecno Spark Slim has already showcased its ultra-thin design, and domestic Chinese manufacturers are joining the fray, adding further excitement to this competition.

I. Apple and Samsung Lead the Way: Pioneers of Ultrathin Flagships

Signs of this new ultrathin phone trend emerged as early as mid-last year. Multiple overseas sources indicated that Apple planned to include an ultrathin model the iPhone 17 Air in its iPhone 17 series. Analyst Ming-Chi Kuo suggested that Apple is attempting to explore new design directions beyond its existing product line; the iPhone 17 Air's focus isn't on hardware specifications but on innovative aesthetics. Leaks and renderings of the iPhone 17 Air have proliferated online. These suggest a horizontal, track-style rear camera module with a single camera, microphone, and LED flash to the right. Specifications are expected to include an A19 chip, a 6.5-6.7-inch screen, 8GB RAM, and a single speaker unit. Due to the thin design constraints, the battery capacity is expected to be above 3000mAh.

The thickness of the iPhone 17 Air is a major point of interest, but concrete information remains elusive. Various figures have circulated online, such as 6.25mm, 6mm, 5.64mm, and 5.5mm. However, recent reports suggest the body thickness might be between 5.5mm and 5.7mm, excluding the camera module.

Although rumors of Apple's ultrathin model surfaced first, Samsung was the first to show tangible results. At the end of its January Unpacked event, Samsung teased a new model with an ultra-thin design the Galaxy S25 Edge. While specific specifications haven't been released, its thin profile was impressive. At MWC 2025, Samsung again showcased the phone, but media were still not allowed hands-on experience or measurements.

Leaks suggest the Samsung Galaxy S25 Edge features a 6.7-inch screen, an aluminum alloy side frame, and a ceramic back. It's expected to use a Qualcomm Snapdragon 8 Gen 3, 12GB RAM, support 25W wired charging, and have a 3900mAh battery. Like the iPhone 17 Air, various thicknesses have been reported, including 6.4mm, 5.85mm, and 5.84mm.

II. Transsion's MWC Showstopper: 5.75mm Thickness and a 5200mAh Battery Breakthrough

If Apple and Samsung manage to achieve a thickness around 5mm, it would represent a revolutionary "paper-thin" breakthrough compared to current mainstream phones. However, thin designs often come at the cost of reduced battery capacity, with leaked ultrathin models generally having under 4000mAh batteries. Pairing flagship chips with such small batteries will inevitably put pressure on thermal management and battery life. So, is the conflict between ultrathin bodies and battery capacity truly insurmountable?

Transsion seems to offer a negative answer. On February 28th, Transsion unveiled the "Tecno Spark Slim," touted as the world's thinnest smartphone, with a minimum thickness of just 5.75mm. Remarkably, despite its slim profile, the phone boasts a 5200mAh battery. In comparison, the Huawei Mate 70 standard edition (released last year) is 7.8mm thick with a 5300mAh battery.

On March 5th, 91Mobile showcased the Tecno Spark Slim at MWC, confirming its remarkably thin design. Compared to the iPhone 16 Pro Max, the Tecno Spark Slim's thinness is considerably more noticeable. Transsion reportedly achieved this ultra-thin design through customized hardware components, such as a custom Type-C port that optimizes space utilization while retaining standard USB-C functionality. They also adapted the battery design to fit a 5200mAh battery into the slim body, with support for 44W fast charging. However, to maintain slimness, the current prototype lacks a SIM card slot.

It's important to note that, like Transsion's Phantom Ultimate 2 foldable phone released last year, the Tecno Spark Slim is still in the conceptual stage, and mass production remains uncertain. Furthermore, due to market strategies, even if it reaches mass production, it might not be officially available in all markets.

III. Domestic Chinese Manufacturers Prepare for Launch: 6000mAh+ Batteries as a Potential Highlight

When news of Apple and Samsung's ultrathin phones emerged, many netizens wondered if domestic Chinese manufacturers would follow suit. According to leaks, several Chinese manufacturers are already planning ultrathin new phones. A Weibo blogger reported on March 4th that the top 5 Chinese manufacturers are all planning Slim series ultrathin phones, featuring flagship platforms and telephoto lenses. Notably, unlike the smaller batteries in Apple and Samsung's phones, these Chinese models aim for battery capacities exceeding 6000mAh.

The target thickness for these Chinese ultrathin models is currently unclear. However, fitting a 6000mAh battery into a 5mm-thin phone would be a groundbreaking achievement. Battery technology is crucial here. IT Home previously reported on battery technology advancements, with silicon-carbon anode batteries enabling last year's new phones to easily exceed 6000mAh, sometimes even reaching 7000mAh, without significant increases in size, potentially even reducing it. As technology advances, overcoming the size limitations of ultrathin phone batteries, allowing for both a slim profile and large battery capacity, could become a reality.

Realistically, achieving both "thinness and full specs" in flagship models is challenging, as flagships need top-tier specifications across the board. However, targeting the "ultrathin" goal for mid-range models is comparatively easier. In fact, some mid-range models already show a clear trend towards thinness. For example, last year's Huawei nova 13 (6.98mm), Honor 300 (6.97mm), OPPO Reno 13 (7.24mm), and vivo S20 (7.19mm) are relatively thin. Further ultrathin designs in this segment would be a significant selling point.

IV. Retro Revival: The Return of Thin and Light

The resurgence of thin and light phones has a distinctly retro vibe. The Samsung Galaxy S25 Edge is expected to be the first mass-produced ultrathin flagship, followed by the iPhone 17 Air and a series of Chinese ultrathin models. In this renewed "ultrathin" trend, who will ultimately win over consumers remains to be seen.