In a statement, the company said Apple, Samsung and others had launched new products and these had sparked a renewal of interest in smartwatches and hearables.
Apart from this, consumers found the money to spend on wearables as they reduced spending on travel, dining out and other leisure activities due to the ongoing pandemic.
Among vendors, Apple took 33.1% market share, with AirPods and Apple Watches proving to be extremely popular. Xiaomi was second with 26.4% of the market; it shipped 17 million units, of which 12.8 million were basic wristbands.
"Many countries began easing restrictions and opening up their economies during the third quarter, which helped bolster outdoor activity as well as demand for wearables," said Jitesh Ubrani, research manager for IDC Mobile Device Trackers.
"Meanwhile, a broader range of price points from numerous vendors meant that there was something for everyone."
Ramon T Llamas, IDC research director, Mobile Devices and AR/VR, added: "The double-digit growth not only indicates strong demand, but also suggests that many people got a wearable device for the first time in both emerging and developed markets.
"Consider what this means: a larger installed base of wearable device users going forward and a larger opportunity for device replacements in the years to come.
"And, as some wearers own multiple devices — like earwear and wristwear — the wearables market will enjoy sustained demand."