People will be able to use the Octopus card on public transport in more than 330 mainland cities starting on Tuesday.
The move means the card can be used on buses, subways, trains and ferries in almost half of the cities on the mainland.
Though the card cannot be used for retail payments in the mainland, it can function as a regular Octopus card when used in the SAR.
The e-payment company said people can purchase the new Octopus-China T-Union card at all Circle K convenience stores and designated MTR customer service centres for HK$88 without a deposit. The card can also store up to HK$3,000.
Octopus also said that people can deposit Hong Kong dollars and the system will automatically exchange to renminbi according to the market exchange rate.
Meanwhile, Octopus also said visitors to Hong Kong can also use the National Renminbi Transit Card to pay for the Hong Kong-Zhuhai-Macao Bridge shuttle bus from Hong Kong to Zhuhai and Macau.