A spa bathroom is really about water and light, so this palette starts with a watery blue-green on the walls — soft, a little grayed, the color of shallow water on a calm day. It is cool but never cold, the kind of tone that lets your shoulders drop the moment you walk in.
A crisp white on the trim and ceiling keeps everything feeling clean and bright, while a pale greige on the vanity or floor tile grounds the scheme and adds a quiet bit of warmth. Soft mist, a touch lighter than the walls, carries through in towels and small details so the room feels layered rather than flat.
The one deeper note is a deep teal, used sparingly on a vanity or framed mirror. It anchors the lightness and gives the whole bathroom a sense of calm depth.