Gobal media tablet shipments rose by 88.9% on a sequential basis and 303.8% year over year in the second calendar quarter of 2011 (2Q11) to 13.6 million units, according to the International Data Corporation (IDC).

IDC’s Worldwide Quarterly Media Tablet and eReader Tracker has now raised its shipment forecast for 2011 to 62.5 million units, up from a previous projection of 53.5 million units.

IDC said that strong demand for Apple’s iPad 2 fueled worldwide media tablet shipments in the second quarter. iPad 2 saw shipments reach 9.3 million units, representing a 68.3% share of the worldwide market (up from 65.7% the previous quarter).

BlackBerry maker Research in Motion (RIM) also benefited by entering the media tablet market in 2Q11 with its PlayBook product, grabbing a 4.9% share of the market, said IDC.

The company said that Apple’s strength and RIM’s entrance meant bad news for Android-based media tablets, which saw its collective share slip to 26.8%, down from 34.0% the previous quarter.

IDC expects Android to cede additional market share in 3Q11 (dropping to 23%) before it starts growing its share again in 4Q11 (increasing to 25.9%) and beyond.

Mobile Connected Devices research director Tom Mainelli said media tablet shipments grew at a solid pace in the second quarter, led by continued strong demand for Apple products.

"We expect shipment totals to continue to grow in the third and fourth quarter, as additional vendors introduce more price-competitive Android products into the market and Apple works to maintain its dominance in the category," Mainelli added.