Samsung continued to lead the smartphone market in the third quarter of 2012, with an estimated 56.3 million devices shipped worldwide according to IDC. That's a massive 31.3% share of the 179.7 million units shipped during the quarter, up from 22.7% a year ago, and double the 26.9 million phones shipped by Apple in the same time frame.

Combined, the two companies took 46.3% of all shipments while Nokia and RIM continued their downward spiral. Although the BlackBerry maker was the third-biggest in the sector, it only shipped 7.7 million devices during the quarter, down from 11.8 million a year ago. Meanwhile, Nokia fell off the list of top five smartphone vendors for the first time, behind ZTE and HTC, with just 6.3 million units.

Although IDC did not break down mobile OS share figures, Apple's shipments equate to a 15% share for iOS, up from 13.8% a year ago, while an earlier report by the market research firm puts Android at around 70%.

All told, 179.7 million smartphones shipped last quarter, representing a 45% percent gain over the prior year. The broader market for all mobile phones grew by just 2.4% from 434.1 million to 444.5 million, meaning that smartphones were 40.4% of all phone shipments. When factoring in feature phones, the market was still dominated by Samsung with 105.4 million shipments globally, followed by Nokia with 82.9 million.

Top Five Smartphone Vendors, Shipments, and Market Share, 2012 Q3 (Units in Millions)

Vendor 4Q11 Unit Shipments 4Q11 Market Share 4Q10 Unit Shipments 4Q10 Market Share Year-over-year Change
Samsung 56.3 31.3% 28.1 22.7% 100.4%
Apple 26.9 15.0% 17.1 13.8% 57.3%
RIM 7.7 4.3% 11.8 9.6% -34.7%
ZTE 7.5 4.2% 4.1 3.3% 82.9%
HTC 7.3 4.0% 12.7 10.3% -42.5%
Others 74.0 41.2% 49.9 40.3% 48.3%
Total 179.7 100.0% 123.7 100.0% 45.3%