Tesco Mobile is a mobile virtual network operator (MVNO) operating in the UK, Ireland, Slovakia and the Czech Republic. It is operated by Tesco, the British retailer, and piggybacks off the network O2. In Ireland, it piggybacks off Three. It was established in 2003 as a low-cost, pre-paid mobile network online and within Tesco stores. In January 2014, the network started supporting the 4G network for its pay monthly and sim only customers. In December 2006, Tesco Ireland announced that it would enter into a joint venture with O2 Ireland to offer mobile telecommunications services. The service, which was Ireland's second MVNO used the O2 network but operates separately. It has been allocated the area code 089. As with Tesco's mobile service of the United Kingdom, it is branded Tesco Mobile. The network commenced operation in 2007. Tesco Mobile had 375,000 customers in Ireland as of August 2017. In March 2015, after it was announced that Three had purchased O2's Irish operations, it was announced that the O2 Ireland network would close and that the O2 website, shops and network would merge into Three Ireland. As a result, Tesco Mobile Ireland moved from the O2 network to the Three network. Since August 2018, Tesco Mobile customers can access Three masts, which means that they can now avail of 4G as well as increased 3G coverage. In May 2013, Tesco Stores ČR a.s. announced that it would enter into a joint venture with Telefónica Czech Republic to offer mobile telecommunications services. The service uses the O2 network.