The filing frequency will depend on the size of your business and the current arrangements made with CRA.
Most small business corporations file their GST/HST on a quarterly basis determined on the fiscal year of the business. Thus a fiscal year end of January would result in quarterly filings due 30 days after the end of the quarter. Thus in this example, the quarters would end April 30, July 31, October 31 and January 31.
It is possible that a business might have GST/HST quarter on a time interval different than their fiscal year term. It would be practical to change this filing pattern to agree with the fiscal year of the business for income tax filing purposes.
Contact your accountant or CRA for additional information.
Some small business entities file on an annual basis. The due date is 3 months after the GST/HST ending period.
Corporation tax returns are due within 6 months after the fiscal year end.
T4 and T5 summaries and slips are due by the end of February of the following calendar year.