Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Belfast to Québec City as you normally would.
Québec City (YQB) is the airport you will fly into if you book a flight from Belfast to Québec City. You should not have trouble finding flights to Quebec from Belfast; the airport handles an average of 0 inbound flights from Belfast per day. You should also have plenty of airline options to choose from since 0 airlines have flights to the Québec City airport from Belfast. It is only a 8.4 mi journey from Quebec (YQB) to Québec City’s city center.