The Nonesuch River is a tidal river in Scarborough, Maine, offering a winding, protected paddle through coastal marshland. The primary public access for paddlers is the boat launch at the end of Clay Pit Road, which provides a free launch with ample parking but no public bathrooms. A secondary, more ocean-oriented launch is available at Ferry Beach at the end of Ferry Road, where a sandy, gradual put-in is suitable for kayaks and paddleboards; parking fees are collected here between 9 a.m. and 5 p.m., with restrooms and showers available. The character of the paddle changes significantly with the tide, which creates a strong current at its peak. For a typical four-hour upstream paddle from the Clay Pit launch, it is advised to put in 30 to 45 minutes before the high tide time listed for the nearby beach, using the incoming tide to assist the journey upstream; note that high tide occurs later further inland. Paddling at high tide is generally recommended for easier navigation and access to the marsh's smaller channels.

The river is characterized by sharp, fun-to-navigate corners and a width sufficient for paddling side-by-side. The route passes under a railroad trestle and Black Point Road (Route 207). Beyond this bridge, paddlers may encounter downed trees requiring careful passage. The environment transitions from saltier water near the mouth to more freshwater upstream, with a variety of plant life and wildlife including egrets and herons. The sounds of traffic near Black Point Road give way to a feeling of remoteness. The river eventually leads to expansive marsh fields, and a decision point where continuing right stays on the main river channel while going straight leads into a pond. The mouth of the river opens near Pine Point and Prout's Neck, exposing paddlers to ocean swell; this area is more exposed than the protected upper river. Duck blinds along the river indicate hunting activity in the fall. The paddle is considered suitable for beginners comfortable with basic strokes, though the strong tidal currents and potential for four-hour trips suggest paddlers should have some endurance. Motorboat traffic is a potential hazard, particularly near the river's mouth.