Probably the largest sea in the world of Redwall, bordering off the Western Coast, the Western Sea (also referred to as the Western Ocean), varies in climate. Its northern waters are bitterly cold, but further south are tropical isles.
In the distantly western part of this sea is the isle of Sampetra, a beautiful tropical isle. It was once conquered by the pine-marten corsair, Ublaz Mad Eyes, who styled himself its emperor and made it a haven for the corsairs who are so common in the Western Sea. Nearby is the Holt of Ruddaring, which was once home to monstrous Monitor Lizards, but was liberated by otters.
In the southern part of the sea is Green Isle, an otter kingdom that was once conquered by wildcats from further south, but which was recaptured in the reign of Riggu Felis with help from Tiria Wildlough.
Between the northern and southern part of the sea lie the Green Maelstrom, a gigantic whirlpool and origins of the Roaringburn Current, and the Island of the Wrecked Ships, where many ships had crashed along its rocky shores.
The Western Sea appears in: Mossflower, Mariel of Redwall, Salamandastron, The Bellmaker, Outcast of Redwall, Pearls of Lutra, The Long Patrol, The Legend of Luke, Lord Brocktree, Triss, Rakkety Tam, High Rhulain, Eulalia!, and The Rogue Crew.