18 Oct 26 Payment of tax for the Jul-Sep quarter by taxpayers under the Composition Scheme.

20 Oct 26 Monthly return by persons outside India providing online information and database access or retrieval services, for September.

20 Oct 26 To add/amend particulars (other than GSTIN) in the GSTR-1 of September. Can be filed after filing GSTR-1 but before filing the corresponding GSTR-3B.

20 Oct 26 Summary return cum payment of tax for September by monthly filers (other than QRMP).

21 Oct 26 Filing of the Tax Audit Report, where the due date of the ITR is 30 November.

22 Oct 26 Add/amend particulars (other than GSTIN) in the GSTR-1 of the Sep quarter, by quarterly filers in Chhattisgarh, Madhya Pradesh, Gujarat, Maharashtra, Karnataka, Goa, Kerala, Tamil Nadu, Telangana, Andhra Pradesh, and the Union Territories of Daman and Diu, Dadra and Nagar Haveli, Puducherry, Andaman and Nicobar Islands, and Lakshadweep. Can be filed after filing GSTR-1 but before filing the corresponding GSTR-3B.

22 Oct 26 Summary return for the Jul-Sep quarter by quarterly filers in Chhattisgarh, Madhya Pradesh, Gujarat, Maharashtra, Karnataka, Goa, Kerala, Tamil Nadu, Telangana, Andhra Pradesh, and the Union Territories of Daman and Diu, Dadra and Nagar Haveli, Puducherry, Andaman and Nicobar Islands, and Lakshadweep.

24 Oct 26 Add/amend particulars (other than GSTIN) in the GSTR-1 of the Sep quarter, by quarterly filers in Himachal Pradesh, Punjab, Uttarakhand, Haryana, Rajasthan, Uttar Pradesh, Bihar, Sikkim, Arunachal Pradesh, Nagaland, Manipur, Mizoram, Tripura, Meghalaya, Assam, West Bengal, Jharkhand, and Odisha, and the Union Territories of Jammu and Kashmir, Ladakh, Chandigarh, and Delhi. Can be filed after filing GSTR-1 but before filing the corresponding GSTR-3B.

24 Oct 26 Summary return for the Jul-Sep quarter by quarterly filers in Himachal Pradesh, Punjab, Uttarakhand, Haryana, Rajasthan, Uttar Pradesh, Bihar, Sikkim, Arunachal Pradesh, Nagaland, Manipur, Mizoram, Tripura, Meghalaya, Assam, West Bengal, Jharkhand, and Odisha, and the Union Territories of Jammu and Kashmir, Ladakh, Chandigarh, and Delhi.

25 Oct 26 Half-yearly details of goods/capital goods sent to and received from job workers, for Apr-Sep, for turnover above ?5 crore.

26 Oct 26 Filing of the Cost Audit Report for 2025-26 by companies to whom cost audit applies (within 30 days of submission by the Cost Auditor).

28 Oct 26 Return for September by persons with a Unique Identification Number (UIN), such as embassies, to claim a GST refund on goods and services purchased by them.

29 Oct 26 Filing of financial statements for FY 2025-26 by companies (other than OPCs), with the ROC (within 30 days of the AGM).

29 Oct 26 Report on the AGM by a listed company, where the AGM was held on 30 September (within 30 days of AGM completion).

29 Oct 26 Statement of Accounts and Solvency for 2025-26, to be filed by every LLP.

30 Oct 26 Half-yearly return by Nidhi companies for April to September.

30 Oct 26 Deposit of TDS on payment made u/s 393(1) [Table Sl. No. 2(i), 3(i), 6(ii)] for purchase of property, and payment of rent above ?50,000 pm by an individual or HUF (not liable to tax audit) where the lease has terminated, and certain other payments made by an individual/HUF, for September. (Rent TDS: else to be deposited on an annual basis by 30 April of the next year, for total rent above ?50,000 pm paid during Tax Year 2025-26.)

31 Oct 26 Employees' Enrolment Campaign 2026 allows enployers to enrol left-out employees (who joined between 01.04.2009–31.03.2026) at a nominal ?100 damages, with employee share waived if not previously deducted — available even to establishments under inquiry.

31 Oct 26 Option to avail QRMP for Oct-Dec onwards.

31 Oct 26 Specified companies (receiving supplies from Micro & Small Enterprises, with outstanding dues exceeding 45 days) to file details of all outstanding dues to Micro or Small Enterprise suppliers, for Apr-Sep. Details of MSME vendors must be given even where payment was made within 45 days.

31 Oct 26 Furnishing of declaration u/s 80GG in respect of rent paid for residential accommodation, if the assessee is required to submit the ITR by 31 October.

31 Oct 26 Furnishing of particulars for claiming relief u/s 89, if the assessee is required to submit the ITR by 31 October.

31 Oct 26 Online application by a domestic company (other than one to whom transfer pricing provisions apply), for exercise of the option u/s 115BAA (22% tax).

31 Oct 26 Online application by a new manufacturing domestic company (other than one to whom transfer pricing provisions apply), filing the ITR for the first time, for exercise of the option u/s 115BAB (15% tax).

31 Oct 26 Online application by an individual/HUF carrying on business or profession, for exercise of the option u/s 115BAC(1), where the due date of the ITR is 31 October.

31 Oct 26 Online application by a resident co-operative society, for exercise of the option u/s 115BAD(1), where the due date of the ITR is 31 October.

31 Oct 26 Online application by a resident manufacturing co-operative society, for exercise of the option u/s 115BAE(1), where the due date of the ITR is 31 October.

31 Oct 26 Statement of foreign income offered for tax for the previous year, and of foreign tax deducted or paid on such income, if the due date of the ITR is 31 October.

31 Oct 26 Filing of income tax returns by companies, partnership firms etc. (audit applicable).

31 Oct 26 Filing of the report u/s 92E for international transactions and specified domestic transactions.

31 Oct 26 Filing of the Audit Report u/s 80JJAA(2) for additional employment, where the due date of the ITR is 30 November.

31 Oct 26 Filing of other Audit Reports, where the due date of the ITR is 30 November.

31 Oct 26 Quarterly TDS/TCS statements for Jul-Sep. Details of Form 121 (15G/15H) cases are also to be shown in Form 140. (TCS filing date has also been aligned with TDS.)

31 Oct 26 Deposit of TDS on Virtual Digital Assets u/s 393(1) [Table Sl. No.8(vi)] for September.

31 Oct 26 E-filing of information on declarations received in Form 97 (60), up to 30 September.

31 Oct 26 Statement of Financial Transactions by depositories, registrars and share transfer agents, reporting capital gains on transfer of listed securities or mutual fund units, for Apr-Sep.