GST Due Dates for the Rest of August and September 2026

Every GST deadline still to come in August and September 2026, in one place for Tamil Nadu businesses. Two September dates fall on a Sunday, and GST due dates do not move for weekends.

Here is every GST deadline still ahead in August and September 2026. Weekday placement has been checked against the calendar; note that GST due dates do not shift when they fall on a Sunday or a holiday.

Rest of August 2026

Thursday 20 August — GSTR-3B for July, monthly filers, with tax payment.
Tuesday 25 August — Form GST PMT-06 for July, QRMP taxpayers.

September 2026

Thursday 10 September — GSTR-7 for August, TDS deductors, and GSTR-8 for August, e-commerce operators collecting TCS.
Friday 11 September — GSTR-1 for August, monthly filers.
Sunday 13 September — Invoice Furnishing Facility for August, optional, QRMP taxpayers; GSTR-6 for August, Input Service Distributors; GSTR-5 for August, non-resident taxable persons.
Sunday 20 September — GSTR-3B for August, monthly filers, with tax payment; GSTR-5A for August, OIDAR service providers.
Friday 25 September — Form GST PMT-06 for August, QRMP taxpayers.

The two Sundays are worth planning around. 13 September carries the IFF and the ISD return, and 20 September carries monthly GSTR-3B. Neither moves to the Monday. The portal is also at its slowest on the evening of a due date, so the practical advice is to file on the Friday before rather than the Sunday itself.

One sequencing point that costs people money every month: under Section 39(10) you cannot file GSTR-3B for a period until GSTR-1 for that same period has been furnished. If GSTR-1 slips, GSTR-3B is blocked behind it and late fees run on both.

File at https://www.gst.gov.in and check the portal for any last-minute advisories at https://www.gst.gov.in/newsandupdates before a deadline.

Topics:GST due dates September 2026GSTR-3B due dateGSTR-1 due datePMT-06 QRMPGSTR-7 TDSGSTR-8 TCSIFF due dateGST calendar ChennaiTamil Nadu GST due datessection 39(10)

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