The Following are CRA Due Date Payment and Filing Deadlines...
If the due date falls on a holiday the deadline moves to midnight of the following business day. If the due date falls on a Saturday or Sunday, the deadline moves to midnight of the following Monday.

T1 Personal Tax Payment Deadline: April 30
T1 Personal Tax Filing Deadline: April 30
Individuals must file their income tax returns by April 30 of the year following the tax year for which the return is being filed.

T4s, T4As and T5s Filing Deadline: February 28
Last day for employers to issue T4s, T4As to employees and T5s to shareholders and submit then to the Canada Revenue Agency (CRA).

T2125 Self-Employed Tax Payment Deadline: April 30
T2125 Self-Employed Tax Filing Deadline: June 15
For people who are self-employed, the CRA filing deadline is June 15, but it begins assessing interest on your tax due on April 30.

T2 Corporate Tax Payment Deadline: 3 Months after Your Fiscal Year End
T2 Corporate Tax Filing Deadline: 6 Months after Your Fiscal Year End
For corporations, the CRA filing deadline is 6 months after your fiscal year end, but it begins assessing interest on your tax due 3 months after your fiscal year end.

GST/HST Annual Payment Deadline with a Fiscal Year End that is Not December 31: 3 Months After Your Fiscal Year End
GST/HST Annual Filing Deadline with a Fiscal Year End that is Not December 31: 3 Months After Your Fiscal Year End
For GST, the CRA filing and payment deadline is 3 months after your fiscal year end.

GST/HST Annual Payment Deadline with a Fiscal Year End that is December 31: April 30
GST/HST Annual Filing Deadline with a Fiscal Year End that is December 31: June 15
For GST filed and paid annually, the CRA payment deadline is April 30 and the filing deadline is June 15.

GST/HST Monthly and Quarterly Payment Deadline: One Month After the End of the Reporting Perod
GST/HST Monthly and Quarterly Filing Deadline: One Month After the End of the Reporting Perod
For GST filed and paid monthly and quarterly, the CRA filing and payment deadline is one month after the reporting period.

T1 Early Filing: Early February
Additionally, if you want to file early, the CRA opens its NETFILE service to electronically receive submitted returns in early February each year.

T1 Early Payments: March 15, June 15, September 15, and December 15
If you wish to make instalment payments on your income tax, your payments are due four times throughout the year on the 15th of March, June, September, and December.

T1 & T2 Late Filing Penalties
If you file your return late, a penalty of 5% of the unpaid tax that is due on the filing deadline, plus 1% of this unpaid tax for each complete month that the return is late.

GST Filing Penalties
If you receive a demand to file and don't, the penalty is $250.00.