Hello! My Fiance and I both applied as single applicants and have received our COPR's and are planning on getting married in October and move to Canada in December. Do we need to inform IRCC of our marriage even though both of us have already received our respective COPRs? Also, what would happen if we do not inform them? We do not want to do a soft landing before our marriage as its an expensive trip and we are planning on moving permanently in December anyways.
Are you travelling together?
Absolutely no need to inform because one is not adding the other as a dependant and no COPRs will need to be reissued.
Well, 'no need' - in fact a matter of judgment / a choice for them to make.
You're correct in that, although they are
required to inform IRCC before landing, it likely won't make much difference because any 'punishment' for not informing IRCC is likely to be limited to ... not allowing either of them to sponsor their spouse (that spouse) in future. Which of course is not likely to be an issue since they're both basically immigrating at the same time on their own merit.
And yet: a fantasist could come up with scenarios, more or less plausible, unlikely, crazy or even borderline-unthinkable, where it could cause issues later. Hypothetically.
Granted, low probability and perhaps not worth worrying about.
On the other hand, some of those scenarios aren't perhaps all that much different or far-fetched than two applicants getting COPR independently and deciding to get married before landing, or, you know, a global pandemic that more or less halts international travel for a couple years.
Up to the applicants how they want to proceed.
Safest would be to contact IRCC and see if one can be added to the other's without additional steps since both already have COPRs in hand and have done medicals and all other clearances anyway. Probably could be done by IRCC by december or indeed well before that (although possibly a bit tight since october marriage).
Also possible IRCC would just say "don't worry about it" and informally tell them to travel.
If it were me I'd perhaps be inclined to travel together, and during the landing process, declare that marriage to the officer while specifying both have already qualified and have independent COPRs. But I don't know.