Casco Bay is a large coastal bay in Maine, renowned for its extensive island network, often referred to as the Calendar Islands for their reputed number. The bay's character is defined by its varied coastline of beaches, coves, inlets, and salt marshes, offering a complex and engaging environment for sea kayaking, canoeing, and stand-up paddleboarding. The paddling experience ranges from calm, protected waters suitable for beginners to more exposed crossings that require careful planning. Key public access points for launching include East End Beach in Portland, Mere Point in Brunswick, and locations in Harpswell. The area is tidal, with a significant range that can expose land bars and drastically alter the shoreline; paddlers must carefully time their trips with the tide cycle. A common strategy is to paddle out during an ebb tide and return during a flood tide to work with the currents. Morning paddling is generally recommended as sea conditions are calmer before afternoon winds develop. The bay experiences substantial motorized boat traffic, including ferries and lobster boats, requiring constant awareness, especially when crossing channels. Hazards include potentially aggressive tidal flows, changing weather and wind conditions, and the recommendation from local paddlers against using very short kayaks or canoes due to the open water conditions. Notable sights include numerous uninhabited islands available for camping, with wildlife such as porpoises, seals, eagles, and osprey commonly observed. Several local outfitters, including Portland Paddle and Casco Bay Kayak, operate from mid-May to mid-October, offering rentals, tours, and lessons, which indicates the primary paddling season. These businesses are situated to take advantage of the bay's geography, providing guided trips that adapt to weather, wind, and tides.