The most common and direct synonym for traveling by boat is sailing, though this often implies the use of wind power. A more modern and general term is boating, which covers everything from small motorboats to yachts. For long-distance sea travel, the term is voyaging or seafaring, while traveling on a commercial passenger ship is specifically called cruising. If the journey involves crossing a specific body of water, it is often referred to as a passage or a crossing (e.g., a "Transatlantic crossing"). For shorter, regular trips across rivers or channels, the term is ferrying. In more formal or nautical contexts, you might use the word navigation or transit. If the travel is specifically for exploration, it is called a maritime expedition. Finally, if you are looking for a more poetic or archaic term, plying the waters describes a vessel that moves regularly over a certain route. Each term carries a slightly different nuance depending on the vessel's size, the distance covered, and the purpose of the trip.