The high-end, dust- and waterproof Sony Xperia Z Ultra smartphone is now available on Three UK, the carrier has announced.

Three is offering the Sony Xperia Z Ultra with a standard two-year agreement, with a starting price of £99 upfront for the handset on a 24-month contract. Plans start at £34, which will get customers 500MB of data, as well as unlimited calls and texts.

"With Sony's largest HD smartphone screen yet, at 6.4", the lightweight Sony Xperia Z Ultra smartphone on Three is perfect for those that want to enjoy entertainment on the move and is available now from Three stores. The Sony Xperia Z Ultra is 4G ready and when Three rolls out its 4G network, a simple, free software upgrade will mean the speedier technology will be available to customers at no extra cost," announced the carrier.

"The Sony Xperia Z Ultra is an exciting addition to our growing range of 4G Ready devices. Its stunning screen and suitability for watching movies or playing games means you can make full use of Three's all-you-can-eat data plans and enjoy an immersive entertainment experience without being tied to your living room," added Sylvia Chind, head of devices at Three.

The Sony Xperia Z is still shipping to the UK but the handset is already available from several retailers. Moreover, the smartphone will soon become available on a number of mobile carriers as well.

For those unfamiliar with the Sony Xperia Z Ultra, the phablet is designed with durability in mind and is both dust- and waterproof. It sports a massive 6.4-inch Full HD display with a resolution of 1920 x 1080, packs the latest Qualcomm Snapdragon 800 quad-core processor and 2GB of RAM.

The handset comes with 16GB of internal storage capacity and a micro SD card slot for additional memory. Other specs of the Sony Xperia Z Ultra include a powerful 3,000 mAh battery and an 8-megapixel Sony Exmor RS camera. The phablet runs on Android 4.2.2 Jelly Bean.

Interested phablet shoppers in the UK who want to order the Sony Xperia Z Ultra online from Three can do so starting from Oct. 18 on the carrier's website. For now, the phablet is only available in Three stores.