St. John's International Airport (YYT) has regular flights to Toronto, Montreal, and Halifax, with connections to most major Canadian cities. The airport is about 5 kilometres northwest of the city centre; taxis are the standard way in.
By road, St. John's is about 300 kilometres from Gander and 350 kilometres from the Port aux Basques ferry terminal via the Trans-Canada Highway. Marine Atlantic operates ferries from North Sydney in Nova Scotia to Argentia (18-hour crossing) and Port aux Basques (6-hour crossing), from which it is a long drive east. The Argentia ferry is the more direct crossing if your destination is St. John's.