Banks don't go to work on Sundays, so they need to go to the counter to activate during bank working hours (Monday to Saturday), or they can activate themselves in official website.

Taking China Merchants Credit Card as an example, the online activation steps are as follows:

Open official website;

In the upper right corner of the page, select and click Open Card to set the password;

Tick I agree to the above contract;

Enter your card information and personal information as prompted;

Set the inquiry password, and you can use it after opening the card.

Online activation varies from bank to bank. It is best to call customer service to find out that it is being activated, and it will not be activated directly at the bank counter.