Due dates for GSTR-3B returns: electronic filing required and liabilities must be paid from electronic ledgers by the return due date. Returns in FORM GSTR-3B for the months July 2018 to March 2019 must be furnished electronically through the common portal on or before the twentieth day of the succeeding month. Registered persons must discharge tax liabilities, interest, penalty, fees or other amounts by debiting the electronic cash ledger or electronic credit ledger, as applicable, not later than that specified due date.