Moriches Bay is a broad, shallow saltwater bay on the south shore of Long Island, New York, forming part of the Atlantic Intracoastal Waterway. The bay is characterized by a sandy bottom, with depths often reported as just inches below the keel in many areas, making it ideal for shallow-draft craft like kayaks and paddleboards. The scenery transitions from broad, grassy banks in some sections to developed shorelines with houses and docks in others, particularly as you move through connecting canals like the Quantuck and Quogue Canals. Paddlers should be aware of significant motorboat traffic, especially during summer months and notably through the Moriches Inlet area, which is marked by active channels. The inlet itself is noted on charts as having rapidly changing shoaling conditions and is considered unsafe for mariners to navigate, indicating a hazard that advanced paddlers should treat with extreme caution.

Several formal and informal launch points provide access. The New York State Department of Environmental Conservation (NYSDEC) maintains the Moriches Waterway Access Site at Hart's Cove, featuring a hard surface launch suitable for small boats and kayaks with parking for 12 cars and trailers; a note advises to launch and recover at high tides. Other municipal ramps include the Forge River Ramp in Mastic and the Maple Ave Ramp in East Moriches, though these may require fees or permits. Silly Lily Fishing Station in East Moriches offers a small boat ramp suitable for kayaks for a slip fee, with parking and toilet facilities, though parking can fill up. Swezey's Marina also offers kayak rentals from a protected cove within the bay, noted for having less worry from big waves and boat traffic. For beginners, Hart's Cove to the north of the access site is considered suitable except in strong east or southeast winds, while the open bay and inlet areas are recommended for experienced paddlers only due to boat traffic and conditions.

Tidal influence is present, with one source noting a 1-foot tidal range at Hart's Cove, but currents can be significant near inlets and channels. Wind exposure is a key factor, as the broad, shallow nature of the bay can quickly develop chop, and strong east or southeast winds specifically make Hart's Cove less suitable for beginners. The area is used for guided paddleboarding events, including sunset paddles and group trips to local beaches like Gull Island and Holiday Beach, indicating its popularity for recreational paddling. These organized events sometimes employ safety boats to manage paddlers away from boat traffic during busy times, such as fireworks displays.