Massachusetts Bay is a large, open coastal bay on the Atlantic Ocean, presenting a spectrum of paddling conditions from sheltered harbors to exposed open water crossings. The bay's northern and western shores offer protected launch points, such as Plymouth Harbor, which is a calm, sheltered area ideal for beginners with minimal current and manageable wind and waves due to its natural geography. Launching from the town waterfront near Cole's Hill provides easy access, with ample parking and facilities nearby. Further north, the area encompassing the mouths of the Danvers River and harbors like Salem, Marblehead, Gloucester, and Manchester-by-the-Sea offers numerous launch sites but presents significantly more challenging conditions. This region is not suitable for beginners, featuring very strong and complex tidal currents, challenging wind chop, and deep water far from shore that approaches open ocean conditions. Paddling fatalities have occurred in these waters, emphasizing the need for experience and serious safety preparations.

For the highly experienced sea kayaker, the bay offers the formidable challenge of a continuous open-water crossing from Cape Ann to Cape Cod, a journey of approximately 47 miles that takes over 13 hours and is conducted completely out of sight of land. This expedition requires meticulous planning around a multi-day weather window, as conditions must be exceptionally stable to avoid being caught miles from shore in high winds or storms. Within the more protected areas, paddlers can explore historic sites like the Mayflower II replica in Plymouth Harbor or visit islands such as Misery Island and Crowninshield Island, which are properties of the Trustees of Reservations and offer hiking trails or rest stops. Tides significantly influence paddling, with high tide generally offering better access in harbors as low tide can expose restrictive mudflats. Afternoon winds can pick up, making morning paddles preferable for calmer conditions. The best paddling season runs from March through November, with summer providing the warmest water and most stable weather, while spring and fall offer fewer crowds.