The Necanicum River flows through the east side of Seaside before emptying into the Pacific just north of the Prom. Most visitors walk straight past it headed for the beach, which is a mistake. The lower river is calm, navigable by kayak and canoe, and offers a completely different perspective on the town — marsh grasses, shorebirds, and the quiet you won't find on Broadway or the Prom. Kayak rentals are available in town.
The river mouth area is also a good spot for birdwatching, particularly during spring and fall migration. Great blue herons are permanent residents. The estuary provides nursery habitat for several salmon species, and there is catch-and-release fishing for sea-run cutthroat trout in the river. The Necanicum extends upstream into the Coast Range, and the valley it runs through is visible from the upper stretches of the Tillamook Head Trail.