Codenamed Togari and marketed as "the world's slimmest Full HD smartphone[5] it is the first phone that allows users to take notes or draw on with a regular pen or pencil.

Combining tempered glass on both the front and rear with a metallic frame, the phablet is described as an "attractive-looking gadget" which has "minimalistic" yet "stylish" appeal and "premium feel".

[13][14][15] The 6.44" Full HD (1080p) 342 ppi touchscreen display uses Sony's Triluminos™ and X-Reality for mobile technology, with an OptiContrast panel to reduce reflection and enable clearer viewing even in bright sunlight.

Because of its size, the phone's on-screen keyboard and dialer can be switched to either sides for users to easily reach all keys with only the thumb.

Sony Xperia Z Ultra is praised for its "very classy" exterior,[6] "stunning" massive Triluminos display, stylish premium design, slim form, light weight, impressive build quality, durability (water and dustproof), interesting pencil/pen compatibility, and powerful specs.

[9] CNET's editor Aloysius Low wrote that "Sony has set a very high benchmark with the Xperia Z Ultra", challenging the leadership position in the phablet market.

[9] PhoneArena wrote that the Xperia Z Ultra is "an engineering marvel" "towering above all other phablets not only in screen size, but also in specs and design".