Sea green is a shade of cyan color that resembles the sea floor as seen from the surface. At left is displayed the web color medium sea green, a medium shade of spring green.

Sea green is notable for being the emblematic color of the Levellers party in the politics of 1640s England. Leveller supporters would wear a sea-green ribbon, in a similar manner to the present-day red AIDS awareness ribbon. It is also a Crayola crayon color, although the Crayola crayon color is much brighter and lighter than the color shown at left.