3 days. According to the query of rural commercial bank credit card information, if the cardholder repays the credit card in full or the minimum repayment amount within 3 days of the credit card repayment date, it will not be considered overdue. Therefore, the grace period for credit card repayment of Jiangnan Rural Commercial Bank is 3 days. Credit cards refer to various media that record cardholder account information, have bank credit lines and overdraft functions, and provide cardholders with related banking services.