It covers 36 square kilometres (14 sq mi) of area on 16 islands and more than 30 islets, reefs and surrounding waters, making it the sixth smallest national park in Canada.

On the federal level, the local member of parliament David Anderson advocated for an organized conservation effort[3] and Minister of Fisheries Jack Davis commissioned, in 1971, a feasibility study of establishing a marine park.

Both the federal and provincial governments pledged $30 million each to acquiring land for conservation purposes generally in the Strait of Georgia area but with the intent of establishing a national park.

The park, along with the Strait of Georgia Lowlands natural region, is situated in a low-lying coastal area surrounded by mountains.

The park includes a climate monitoring station, in operation since 1989, on Saturna Island;[8] the area experiences an average of 838 mm (33 in) of precipitation each year, with over half of that falling in the four-month period between October and February.

The terrestrial portion of the park lies within what the province terms the Coastal Douglas-Fir Biogeoclimatic Zone based on the climax vegetation.

[9] In the sea waters swim orcas, porpoises, seals, salmon, lingcod, shiner perch, saddleback gunnel and three-spined stickleback, among others.

Birds that be seen in the park include cormorant, bald eagle, red-tailed hawk, falcon, turkey vulture, rhinoceros auklet, Brant geese, great blue heron, Hermann's Gulls, and oystercatcher.

[9][10] The park consists of 31 km2 (12 sq mi) of land and 6 km2 (2 sq mi) of water scattered over and around 16 islands and more than 30 islets and reefs at the southern end of the Gulf Islands archipelago in the Strait of Georgia, Haro Strait and Boundary Pass on the Canadian side of the international border with the United States.

While it covers a 10 ha (25 acres) area consisting of second-growth forest, the site is divided by the Highway 17 and the Swartz Bay Road overpass and surrounded by urban and agricultural development.

Located off the coast of Town of Sidney, in the Haro Strait, it is accessible only by private boat, passenger ferry or small plane via an airstrip further down the island.

Historically, this area had been used by First Nations people for clam harvesting, before being subjected to a failed residential subdivision by the Hudson's Bay Company in 1860, clay extraction for a brickworks between 1906 and 1915, logging of old growth trees, and the introduction of non-native animals like deer and peacocks from farming operations and its use as a private hunting ground[13][14] before the province used the area in the late-1950s to test the concept of a marine park.

[15] Being well-received, the province formalized it as a provincial park in 1961 and developed mooring buoys and an anchoring area, with an on-shore dock for passenger ferries, a campground, pit toilets, and water taps.

Like D'Arcy Island, the province made it into a marine park primarily accessible by sea kayakers on a multi-day trip, with no docking or mooring facilities for motorboats, and added backcountry campsites with pit toilets but no potable water.

Similarly, evidence remains of its use as a private island, including agricultural development and logging; though, it reverted to the provincial Crown after the owner's bankruptcy in the Great Depression.

The Narvaez Bay park area includes several connected hiking trails, along the coastline and through the forest to the Monarch Head viewpoint which overlooks Boundary Pass and the American San Juan Islands.

At the end of the northern peninsula is a small park area with a sandstone beach that surrounds the East Point Light Station and Fog Alarm Building with the Boiling Reef just off-shore.

The middle of the island is a large park area that covers land from the valley bottom of Lyall Creek to the plateau of Mt.

Tumbo, 121 ha (299 acres) in area and named in reference to a tombolo, was acquired by the province in the Pacific Marine Heritage Legacy program from a Californian for $3.7 million with the provision that he was able to keep his cottage and care-taker suite.

Prior to its use as private property (since 1877) for timber harvesting, coal mining, mink farming, and recreational living, it was used by the Coast Salish people when crossing or working in the strait.

[26] There is a 1.5 km (0.9 miles) hiking trail from a sandy beach, suitable for swimming and launching kayaks, to Campbell Point where there are views of Georgeson Island's old-growth forest on a sandstone ridge.

On the east end of the island, the park site extends from Portlock Point around Richardson Bay to the Bright and Red Islets.