Alaska: If you didn't expect to see Alaska on this list, you'd be right?if we were talking about Alaska's Inside Passage, which is one of the calmest bodies of water in the world. However, any ship crossing the Gulf of Alaska?especially after Labor Day?can experience varying degrees of turbulence.

For travelers prone to seasickness or those seeking a peaceful voyage, the calmest waters are typically found in landlocked or protected seas. The Sea of Cortez in Mexico, often called the "Galápagos of North America," is a prime choice as it is shielded by the Baja Peninsula, resulting in very low wave activity. The Caribbean Sea is also famous for its glassy, crystal-clear waters, particularly during the peak dry season from December to April; however, it is best avoided during hurricane season (August to October) when conditions can become exceptionally rough. Other highly recommended "flat water" destinations include the Inside Passage of Alaska and the Norwegian Fjords, where the surrounding mountains act as natural windbreaks. For those looking for an alternative to the open ocean, river cruises along the Danube, Rhine, or Nile offer a near-motionless experience, as these inland waterways are immune to the swells and tides that characterize even the calmest maritime environments.