Horseshoe Bay/Highway 99
Along Highway 99, just north of Horseshoe Bay, there is a viewpoint a short ways past the Horseshoe Bay turnoff. You can also walk fairly safely from Horseshoe Bay along the highway to the viewpoint (this takes about 10-15 minutes once you reach the highway). Driving there could be a bit more difficult seeing you would probably need to go to Lions Bay first to turn around and come back on the right side of the road. From here you can get a great view of Howe Sound as well as the ferries virtually sailing under your feet!

Horseshoe Bay/Waterfront
Horseshoe Bay itself is a great place to watch ferries. There are always at least 4 ferries coming in and out of the bay every day so you're bound to see one if you're there for long. It can be hard to find parking here and it's often busy. Most times you can walk to the end of Sewell's Marina and watch the ferries come in and load/unload.

West Vancouver/Whytecliff Park
There are some very scenic views from this beautiful park and the Horseshoe Bay - Departure Bay ferries go by here, sometimes quite closely. You can see them until they go out of sight around Bowen Island. You can also see the Bowen Island ferry from a distance from here. A warning about nice summer days and long weekends: Parking here fills up very quickly and it can be quite messy. However, if you drive just past the main entrance there is overflow parking off to the right that usually has room.

Downtown Vancouver/Canada Place
One of the greatest places to watch ships is Canada Place in Downtown Vancouver. From May until September is the cruise ship season and there's usually always one cruise ship docked at Canada Place (north end of Burrard St.). If there's no cruise ship in the way, you can also see the SeaBus go by every 15 minutes. Seaplanes take off and land on the north end of the terminal and from there you can also get a good view of the harbour and the activity around it.

Gabriola Island/Malaspina Point
Malaspina Point is a few kilometers north of the Descanso Bay ferry terminal. Follow Taylor Bay Road to Malaspina Drive then follow that road to the end. It is also the location of the Malaspina Galleries. From here you can see all ferries coming to and from Nanaimo (all 3 terminals). The galleries are really interesting too! (Thanks to John Anderson for bringing this place to my attention. I later visited this site myself.)

Gabriola Island/Orlebar Point
Orlebar Point is a very nice site on the northeast point of the island. Although it is not a park, there is a couple places to park a car. It faces Georgia Strait and has an excellent view of the Duke Point-Tsawwassen ferries rounding the Island to/from Duke Point. To reach it, follow Taylor Bay Road, then Berry Point Road which goes around the point. A very scenic drive or a 1 - 1 1/2 hour walk. (Thanks to John Anderson for bringing this location to my attention. I later visited this site myself, by accident!)

Saltspring Island/Ruckle Provincial Park
This park is located on the eastern tip of Saltspring Island jutting out into Swanson Channel. Most of the ferries going to or coming from Swartz Bay go by here. The park has a campground (mostly walk-in) and several trails through forest and along the shore with nice views of the islands. It is quite a popular spot and fairly busy in the summer.

Mayne Island/Lighthouse Point
There is public access to the area around the lighthouse at the entrance to Active Pass. It's a long walk from the ferry terminal at Village Bay, but if you have a bike or car you could get there easier. I don't think it's worth the trip, but if you're in the area check it out. You can see all the ferries entering and leaving Active Pass and heading to Tsawwassen. The view from here is mainly across Georgia Strait where you can see the Fraser Valley and the Coast Mountains on the horizon.

Galiano Island/Bellhouse Park
Bellhouse Park is right on Active Pass. If you want to be so close to the ferries that they won't fit in your camera's view then this place is for you. It's not much of a park, just a couple acres of rock and grass with some trees (some nice Arbutus trees), picnic tables, benches, and outhouses. On a nice day it's just a nice place to sit and watch the boats go by. It's just a pleasant short walk from the Sturdies Bay ferry terminal (15-20 minutes) and one of my favorite places.

Victoria/Inner Harbour
There is a walkway around most of Victoria Harbour from where you can get views of the ferries and boats going in and out as well as the historical buildings along the waterfront. Nearby is the Ogden Point Breakwater where I have not been as of yet but on the map it looks like it would be a great place to watch boats coming in and going out of the harbour. The map says there's a walkway all the way out to the lighthouse. This breakwater begins on Dallas Rd. at the foot of Montreal St. where there is some parking along the side of the road.

Nanaimo/Duke Point
There's a nice park (Biggs Park and Jack Point Park) along the western side of Duke Point, from the Nanaimo River Estuary out to the end of the peninsula. There is a parking lot on the other side of the highway and a tunnel going under the highway for pedestrians. From the point, which is about 30 minute walk from the parking lot, you can watch the ferries come and go from Duke Point (once every 2 hours) and the ferry across Nanaimo Harbour to Gabriola Island. There is a lot of harbour activity in the vicinity and you can see the city of Nanaimo from here.

Nanaimo/Newcastle Island
Newcastle Island is a provincial park just off shore of the city of Nanaimo. You can catch a passenger ferry (10 minutes) from Maffeo-Sutton Park, which is just a short walk/drive north of downtown Nanaimo. If you're a good swimmer you could probably swim there just as fast, but the boat is good if you don't want to get wet. The hike around the island takes a couple hours and there are lots of beaches and viewpoints. There is a nice viewpoint at the north end where you can watch the ferries come into Departure Bay, every 1 1/2 hours (sometimes more frequently).

Campbell River/Waterfront
There are several parks along the Campbell River waterfront from where you can watch the ferry go across Discovery Passage. Discovery Passage can have very strong currents when the tides are changing. There is a lot of other marine traffic along here and at slack tide, the Alaska/Inside Passage cruise ships go past here.