CSL Mobile Limited

CSL Mobile Limited is a Hong Kong telecommunications company, which operates mobile network brands of "csl", "1O1O" and "Club SIM". CSL is a subsidiary of Hong Kong Telecom (HKT) and was Hong Kong's first mobile communications operator established in 1983, and also the first network to launch the world’s first dual band 4G LTE network with DC-HSPA+.

The brand CSL was under different legal person in its operating history, namely Communication Services Limited, which known as Hong Kong Telecom CSL Limited from 1990 to 1999, and then Cable & Wireless HKT CSL Limited from 1999 to 2001, and then Hong Kong CSL Limited from 2001 (it became a subsidiary of CSL Limited after the formation of CSL New World Mobility), CSL Limited (formerly known as New World PCS) and CSL Mobile Limited; The current legal person of the brand, CSL Mobile Limited, was formally known as PCCW Mobile HK Limited. It was the result of the merger of the brands CSL and PCCW Mobile.