Internet retailer Mobile Fun lists a sim-free, 16GB version of the flagship Android handset as available for pre-order.
The black edition of the Galaxy S3 is said to be identical to the current blue, white and red models in every other way, though its existence is yet to be officially confirmed by Samsung.
Samsung's cutting-edge smartphone launched at the end of May, and is now available in 140 countries. Samsung predicts that the device will surpass 19 million sales by the autumn having reached the 10 million mark last month.
The Samsung Galaxy S3, featuring a 4.8-inch screen and fast quad-core processor, became the fastest-selling pre-order phone of all time following its unveiling, with reports suggesting that it attracted more than 9m advance purchases.
The device served as the official smartphone of London 2012, with its NFC technology granting athletes access to the Olympic village and helping them purchase goods and services.