The Mhuir Sea is the broad body of water lying west of the Skyre Islands. It is one of the principal maritime reference points used in maps and navigation around the archipelago.

For the peoples of the Skyre Islands, the Mhuir Sea is not an empty boundary but part of the wider environment through which fishing, travel, raiding, trade, and the traditions of the Wave Riders developed. Detailed knowledge of its local waters belongs primarily to sailors and coastal communities, while surviving general maps describe the sea only at a much broader scale.