( CNN ) -- Google says the Nexus 7 , its hotly anticipated new tablet computer , is shipping to customers who preordered it this week , amid reports of heavy demand . In an e-mail to customers , the company said some versions of the 7-inch tablet are in the mail and others would be on the way to customers by Thursday evening . `` We 've had incredible demand for the new tablet and are shipping them as quickly as possible , '' read the message . `` If you placed your order by July 11 , it will ship this week , and we 've upgraded to overnight shipping so it arrives sooner . Orders placed after July 11 will ship next week with overnight shipping . '' At its online Help Center , Google says 8 GB versions of the Nexus 7 have already been shipped in the United States . All 16 GB versions that were ordered before July 11 should be shipped by the end of the day Thursday . Orders in the UK and Australia will be shipped later this month . Retailers have been reporting that they 've already sold out of all of the Nexus 7s they 've ordered . Photos surface of a large , early-2000s iPad prototype . CNET reported this week that GameStop , Staples , Sam 's Club and Office Depot already had sold out of the tablet . GameStop told the blog they expected another shipment on August 7 . A quick check of several websites Thursday , including Fry 's and Best Buy , did n't turn up any that say they have the Nexus 7 in stock . There have been scattered reports online of people who say they 've already received a Nexus 7 or found one in stores . But , in an unusual move , Google has not announced an official date they 'll go on sale in retail stores . While all signs point to big sales , Google also remains mum on how many tablets have been ordered or shipped to retailers . In the past , some electronics companies have been suspected of intentionally limiting the supply of new products to create the appearance of strong demand . Last month , Google announced it would be releasing its own , 7-inch tablet . It 's a move that comes in the wake of the relative success Amazon has had with its smaller , less expensive iPad competitor , the Kindle Fire . Analysts say the Kindle Fire sold roughly 16 million of the devices last year . That 's as good as any tablet has done other than the Apple 's iPad . Apple is expected to sell 55 million by the end of this year . The arrival of the Nexus 7 and a possible smaller iPad , however , have many wondering whether it will keep its momentum . Like the Fire , which also has a 7-inch screen , the 8 GB Nexus 7 will sell for $ 199 . A 16 GB version sells for $ 249 . Early reviews have been overwhelmingly positive . Wired magazine called it `` the best Android tablet yet . '' `` The Nexus 7 , the first tablet to wear Google 's Nexus brand , sets a new standard for smaller slates , proving that just because it is n't as big as Apple 's iPad does n't mean it ca n't be just as useful , as fast , or as fun , '' Nathan Olivarez-Giles wrote for Wired , a CNN content partner . The Kindle Fire has been the most successful tablet so far running Google 's Android operating system ( actually a modified version ) . A new version , possibly adding a camera and higher-definition display , is anticipated later this year . Review : Nexus 7 is best Android tablet yet .
Google 's Nexus 7 tablets are on their way . Some pre - orders were shipped on Thursday , Google says . The 7-inch tablet has gotten overwhelmingly positive reviews . So far , similarly sized Amazon Fire is most successful tablet challenger .