first, confirm whether your credit card is dual-currency. I remember that it seems that only dual-currency cards can be used for direct consumption, and UnionPay cards only withdraw money from ATMs in Hong Kong, but have not been used for direct consumption ~ ~ ~

BOC Visa credit cards are dual-currency, and there are two accounts in RMB and US dollars, that is, it is not a problem for you to travel abroad. You can settle in US dollars in the US dollar area and in other areas, but there is a certain currency exchange fee.

unionpay cards (those without VISA logo) can only be settled in RMB. Merchants who support RMB payment will give you a credit card at the market price to convert Hong Kong dollars into RMB (higher than the bank exchange price, and now most of them pay 1% off).

in case of visa, the credit card will be settled according to the foreign currency allowed by the credit card, and the foreign currency arrears will be repaid in RMB or foreign currency.

the repayment of foreign exchange purchased in RMB is calculated according to the exchange rate on the repayment day.

suggestion: pay the RMB required for purchasing foreign exchange in time before going out or before the due repayment date, so as to avoid generating interest and late fees, and apply to customer service for purchasing foreign exchange on behalf of customers in advance.