Do you have to check in with customs/immigation to sail into internal waters?

It’s painfully obvious that if I want to take a boat out from Maine and dock in Nova Scotia for a few days, I am required to check in with Canadian Customs, then check in with US Customs when returning. Am I required to do this if I want to sail into, say the Bay of Fundy or the Gulf of St. Laurence (e.g. sail by Newfoundland, up to Anticosti Island, spend a day taking pictures, sail down through the Northumberland Strait, then up and around Cape Breton Island, and return), do I HAVE to check in with Canadian Customs? I know that it would probably be a good idea, but is there any legal requirement that I must do so if I do NOT go ashore? What about other countries?

I’d certainly appreciate you checking in with me before sailing into my internal waters. :smiley:

Yes.