Sony has unveiled its new Xperia Z Ultra phablet at the Mobile Asia Expo in Shanghai this morning. The device boasts a large 6.4-inch display, the latest Qualcomm Snapdragon 800 processor running at 2.2GHz, and 4G LTE connectivity. Like its little brother, the Xperia Z, the Xperia Z Ultra is also waterproof.

Sony claims the Xperia Z Ultra is the world’s slimmest full HD smartphone, with the largest full HD smartphone display, and the fastest smartphone processor. If you’re into super-sized smartphones, then, this appears to be the one to beat right now. Samsung sure has stiff competition for the upcoming Galaxy Note III.

The Xperia Z Ultra measures just 6.5mm thick, and weighs 212 grams. It has 16GB of storage built-in — 11GB of which is user accessible — and a microSD card slot that’ll take an additional 64GB. There’s a 3,000mAh battery that should keep you going all day long, as well as an 8-megapixel rear-facing Exmor RS camera, and a 2-megapixel front-facing camera.

The Xperia Z Ultra is Sony’s first smartphone with “Triluminos” technology, which promises a wider, richer color gamut. It’s also Sony’s first smartphone to offer the latest Android 4.2 operating system, which the flagship Xperia Z is still waiting for.

But is the Xperia Z Ultra just a little too big? With a 6.4-inch display, it’s only 0.6 inches smaller than many tablets, though its thin bezels and svelte form factor do make it a much smaller device. Nevertheless, it’s certainly going to be a pocket-sweller that’ll need two hands for operation, and it could be blurring the lines between smartphone and tablet just a little too much.

Only time will tell whether the Xperia Z Ultra is a success. We’ll find out more when it launches globally during the third quarter of 2013.

• ViaEngadget