To avoid the 3 hrs drive along the I-5 Hwy and possible extended waits at the Peace Arch border crossing, the fastest & best way on how to get from Seattle to Victoria is by ferry.
Please note that any crossing between the USA & Canada whether by plane, vehicle or ferry requires a valid passport.
Visitors often request ferry travel information on the best way to get from Seattle to Victoria Island and the cheapest way to get to Victoria from Seattle. Victoria Island is in fact located in the Canadian Arctic - but Victoria BC is located on the southern tip of Vancouver Island. The downtown to downtown ferry trip is approximately 2-3/4 hrs.
There is only one ferry system traveling from downtown Seattle to downtown Victoria. The ferry is a high speed 425 seat passenger-only catamaran. Two seat classes are available on the ferry: standard fare seats and comfort class seats.
If planning a stay in Victoria and to maximize travel dollars, one can secure the cheapest Victoria BC Clipper tickets by booking a combo ferry / hotel package.