GSTR-3B filing deadlines require electronic submission via the common portal and payment from e-ledgers by the due date. Returns in FORM GSTR-3B for the months specified must be furnished electronically through the common portal on or before the prescribed last date. Registered persons shall discharge tax liabilities, including tax, interest, penalty, fees or other amounts payable under the Act, by debiting the electronic cash ledger or electronic credit ledger, as applicable, not later than the corresponding last date for filing the return.