The Coos River in Oregon, USA is the primary freshwater source feeding the expansive Coos Bay, the largest estuary on Oregon's southern coast, covering nearly 20 square miles. This tidal river system offers a variety of year-round paddling opportunities characterized by its connection to a working waterfront and protected natural areas. The overall experience involves navigating a dynamic, saltwater-influenced environment with significant commercial and recreational boat traffic, including tugboats, lumber barges, ships, and US Coast Guard vessels. A key area for paddlers is the South Slough, a protected inlet which is home to the South Slough National Estuarine Research Reserve, the nation's first protected estuary. Guided tours are available here, and the tides are utilized to ease paddling, with tours planning to ride the ebbing and flowing currents over distances of approximately 4.6 miles.

Multiple public boat ramps provide access. The Myrtle Tree boat ramp on the South Fork Coos River is a free, beginner-friendly launch point with amenities including a ramp, parking, restrooms, a dock, and ADA accessibility. The upstream docks at this location were removed for maintenance, but the docks along the boat ramp remain usable. Other launches in the broader Coos Bay area include the California Street, North Spit, Eastside, Empire, and Charleston Marina boat ramps. The meeting point for tours in the South Slough is at a bridge on Hinch Road.

Paddling here requires awareness of tidal currents, which are strong enough that guided tours specifically plan routes to harness them. The area supports a rich tapestry of wildlife, with frequent sightings of bald eagles, osprey, great blue herons, brown pelicans, egrets, belted kingfishers, harbor seals, and sea lions. A state regulation requires an invasive species permit for all boats over 10 feet in length. The water is noted for being cold, necessitating appropriate gear such as wetsuits. The historical context includes remnants of early pioneer days and traces of Indigenous culture, adding a layer of interest to the journey.