Marine blue is a shade that represents the ocean and the skies above. This color is calming and soothing, which makes it perfect for a variety of applications, such as home decor, fashion, and graphic design. Synonyms for marine blue include navy blue, deep blue, cobalt blue, azure blue, and indigo blue. These shades are all similar to marine blue but each has their own distinct qualities. Navy blue is a darker shade, while cobalt blue is brighter and more vibrant. Azure blue is a paler shade, while indigo blue has a slight purple undertone. Regardless of the shade you choose, incorporating this color into your design scheme will bring a sense of relaxation and tranquility.