Replacing the Xperia Active, the Go features a 1Ghz dual-core processor and runs Android 2.3 (Gingerbread), upgradeable to Android 4.0 (Ice Cream Sandwich) at some point in the future.
But the Go's headline feature is the hard-wearing design of the handset, which has been achieved without making it look ugly or bulky.
The 3.5-inch Reality Display features scratch-resistant mineral glass meeting international standards for protection against dust and water immersion.
According to Sony, the sleek and stylish handset offers the "highest level of dust and water resistance in a smartphone".
Other features include a 5MP fast-capture camera with LED flash and autofocus, which goes from sleep to shoot in just over a second.
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Users can access the Sony Entertainment Network, as the phone comes pre-loaded with apps for the Music Unlimited and Video Unlimited services for songs and movies respectively.
"With Xperia Go, consumers can watch the latest movies and TV shows in razor-sharp quality and with super-fast performance," said Sony.
"Its sleek and stylish design means durable and water-resistant smartphones no longer have to look bulky and ruggedized."
The Xperia Go will be available in the UK from the third quarter of 2012, offered in black, white and yellow. Pricing has not yet been announced.
The handset will be marketed in the US as the 'Xperia Advance'.