Using ATMs can be expensive over the long haul. If you're withdrawing from a foreign account, there is a limit (usually $300 at Canadian ATMs), and each withdrawal is charged the ATM fee.
I have had NO problems transferring large amounts from abroad into my Canadian bank account. In one case it was from Hong Kong to Canada, in two other cases from the USA into Canada. In each case I alerted my Canadian bank ahead of time. I don't know if that made a difference or not. In all cases the transfer went smoothly.
Just be sure to ask your Canadian bank exactly what information is necessary for the money to find your account.
As far as alerting the tax authorities, I don'tt think Canada is as careful about that sort of thing as the USA is. But even if Canada were tracking your transfers, there is nothing illegal or taxable about transferring your money into Canada. It is any investment income from that cash (interest or stock capital gains, etc) that are taxable, and you pay tax to Canada whether the income is made in Canada or abroad.
If you can pick the time to transfer, keep an eye on the exchange rate, to choose a time when you get more Canadian dollars for your foreign currency. Most Canadian banks will immediately convert the incoming money into Canadian dollars, using the exchange rate of the day. The only control you have is WHEN you make the transfer.
So, in brief, transfer the money you need into Canada by wire transfer, but keep an eye on exchange rates to determine when to do it..
