In its Worldwide Quarterly Wearable Device Tracker, the company said 2.7 million units were shipped in 3Q16, compared to 5.6 million in 3Q15.

It pointed out that 3Q15 was the first in which Apple's Watch was widely available while the second generation Apple product had been on sale only in the last two weeks of 3Q16.

IDC's wearables team research manager Ramon Llamas said: "The sharp decline in smartwatch shipment volumes reflects the way platforms and vendors are realigning.

"Apple revealed a new look and feel to watchOS that did not arrive until the launch of the second generation watch at the end of September. Google’s decision to hold back Android Wear 2.0 has repercussions for its OEM partners as to whether to launch devices before or after the holidays. Samsung’s Gear S3, announced at IFA in September, has yet to be released. Collectively, this left vendors relying on older, aging devices to satisfy customers."

Jitesh Ubrani, senior research analyst for IDC mobile device trackers, added: "It has also become evident that at present smartwatches are not for everyone.

"Having a clear purpose and use case is paramount, hence many vendors are focusing on fitness due to its simplicity."

Ubrani said that in future, differentiating the experience of a smartwatch from the smartphone would be key "and we're starting to see early signs of this as cellular integration is rising and as the commercial audience begins to pilot these devices".

Top Five Smartwatch Vendors, Shipments, Market Share and Year-Over-Year Growth, 3Q 2016 (Units in Millions)
Vendor	3Q16 Unit Shipments	3Q16 Market Share	3Q15 Unit Shipments	3Q15 Market Share	Year-Over-Year Growth
1. Apple	1.1	41.3%	3.9	70.2%	-71.6%
2. Garmin	0.6	20.5%	0.1	2.3%	324.2%
3. Samsung	0.4	14.4%	0.4	6.4%	9.0%
4. Lenovo	0.1	3.4%	0.3	6.2%	-73.3%
5. Pebble	0.1	3.2%	0.2	3.3%	-54.1%
Others	0.5	17.2%	0.6	11.5%	-27.2%
Total	2.7	100.0%	5.6	100.0%	-51.6%
Source: IDC Worldwide Quarterly Wearable Device Tracker, 24 October