Are online casinos legal in Ontario?

Yes, they are. Ontario launched its online gambling market called iGaming Ontario on April 4, 2022. Its online gambling sector now boasts a trove of reputable and reliable licensed casinos.

...

What happens if a transaction is declined?

Some banks are quite strict in that if they detect transactions were made for gambling purposes, they will request for you to close your account.Β  This seems to be more prevalent with RBC and TDC.

...