Market researcher IDC forecasts a boom in sales of wearable devices, especially smart ones, with Google's Android Wear gear gaining ground on the Apple Watch.

By the end of this decade, the battle between the Apple Watch and rival Android smartwatches will be a much tighter one.

That shift will come as consumers get more familiar with smart wearables, still a very new type of gadget for most people, and as those devices surge ahead of more basic wearables such as fitness trackers, market researcher International Data Corp. said in a forecast released Monday, Cnet reported.

For 2015, IDC predicts a wide spread between the Apple and Android camps. The market-dominating Apple Watch and its WatchOS software this year should account for 13.9 million device shipments and a 58.3 percent share of consumers' acquisitions of smart wristwear. Android Wear, found on a variety of devices, including Motorola's Moto 360 and the LG Watch Urbane, will clock in at 4.1 million shipments and a 17.4 percent share.

By 2019, Apple's share will have dipped below the halfway point, to 47.4 percent on shipments of 40.3 million devices, IDC said. The Android side, meanwhile, will be up to 38.4 percent, riding shipments of 32.6 million units.

Other smart-wearables contenders are now and will remain well behind the leaders, according to IDC. Pebble, for instance, will see shipments rise only slightly in 2019, to 2.6 million units as its market share dips to 3 percent, while Samsung's Tizen will edge up to 1.8 million units for a 2.2 percent share.

Smartwatches have been around for several years but none managed to find more than a handful of buyers. The market perked up considerably toward the middle of this year with the arrival of the Apple Watch, the first wearable from the Mac and iPhone maker. The company itself has yet to say how many watches it has sold, but researcher Strategy Analytics reckoned that some 4 million Apple Watches had been shipped by the end of the second calendar quarter.