There is parking at the cathedral but if it is full you can park at the underground car park at Dataran Merdeka (Merdeka Square).
You will need to pay RM3 upon entry which is a discounted rate for those attending Cathedral services. Please then ensure that you get your parking ticket stamped at the Cathedral Book Corner. You will need to present your ticket when you exit the car park and those with stamp are not required to pay any additional amount. Please note the discounted rate of RM3 is only valid on Sundays.