- 21 May 2021 (23rd May 2021 for online payment and filing):
Bi-monthly VAT 3 Return and payment for the period March/April 2021
- 21 May 2021 (23rd May 2021 for online payment and filing):
Corporation Tax Return CT 1 and final payment for companies with accounting periods ending 31 August 2020
- 21 May 2021 (23rd May 2021 for online payment and filing):
Preliminary Corporation Tax due (where liability is less than €200,000) for accounting periods ending 30 June 2021
- 21 May 2021:
Form 46G for companies with accounting periods ending 31 August 2020
