Refers to the School Uniforms worn by the underwater-based characters of Nagi No Asukara. They are basically Serafuku in some sense for both genders.
Boys: Short-sleeved white jacket-like Sailor Shirt with blue Sailor Collar (summer) or long-sleeved blue jacket-like sailor shirt with blue sailor collar (rest of the year) with Blue Pants that do not reach the ankles. Optional Blue Neckerchief.
Girls: Sleeveless white (summer) or long-sleeved blue (rest of the year) Sailor Dress with blue sailor collar and blue Neck Ribbon.