CA in Practice
1340 Points
Joined September 2013
Nowhere it says that GSTR-1 shall be filed before GSTR-3B. It is just because of the due dates. Due date for monthly GSTR-1 is 10th of next month, GSTR-3B is 20th of next month.
in case of quaterly GSTR-1, GSTR-3B is filed first.