The Mandara Spa on Norwegian Cruise Line's "Prima Class" ships—specifically the Norwegian Prima and Norwegian Viva—is widely considered the best in the fleet for 2026. These spas feature a groundbreaking design that includes the first-ever charcoal sauna at sea and a two-story indoor waterfall. The "Thermal Suite" on these newer ships is significantly expanded compared to the older Breakaway-plus class, offering a diverse "salt room" and a cooling "Snow Paradise" set at -10°C to invigorate the respiratory system. The Mandara Spa on the Prima class is also unique for its "observation" design, allowing guests to relax in heated loungers with floor-to-ceiling views of the ocean. While the spas on the Encore and Bliss are also award-winning, the sheer architectural scale and the inclusion of advanced features like the "Experiential Showers" and the floatation salt pool make the Prima-class experience the gold standard for NCL spa enthusiasts.