It is fairly easy, but it would be a hard day trip. I would definitely recommend an overnight in Vancouver. If you have a car it takes about 2.5 hours if there is no traffic at the border. The border can add another hour onto the trip each way. Fridays and Sundays are the heaviest traffic times. There is also a train, Amtrak, that goes from downtown Seattle to Downtown Vancouver. http://www.amtrakcascades.com/ . There is also an online resource to see what the current wait times and a webcam showing the various border crossings. http://www.borderlineups.com. It is much easier to get into Canada and much more difficult to get into the US and therefore you have to schedule more time to get back into the states. There are two border crossings right next to each other, the Peace Arch and Pacific Highway/White Rock.
Vancouver and Seattle are both great cities. Vancouver is twice the size of Seattle, so it is more metropolitan, has better shopping and is very pretty. In some ways it actually reminds me of Sydney... there is a strong Asian influence and it is a fairly modern city of about the same size of Sydney. about 9 years ago
Please help by adding any usefull info on border crossings on our (non profit) wiki on border crossings all around the word: www.crossborder.info and help travelers cross borders!
We hope to grow and provide a usefull collection of tips and tricks on borders crossings, checkpoints, visa info, overland experiences and what's more. Your help will be most appreciated!! about 5 years ago