- 14 January 2018 (23rd January 2018 for online payment and filing):
P30 Monthly Return and payment for December 2018
- 19 January 2018 (23rd January 2018 for online payment and filing):
Bi-monthly VAT 3 Return and payment for the period November/December 2017
- 21 January 2018 (23rd January 2018 for online payment and filing):
Corporation Tax Return CT 1 and final payment for companies with accounting periods ending 30 April 2017
- 21 January 2018 (23rd January 2018 for online payment and filing):
Preliminary Corporation Tax due (where liability is less than €200,000) for accounting periods ending 28 February 2018
- 21 January 2018:
Form 46G for companies with accounting periods ending 30 April 2017