Shamrock was a racing yacht built in 1898 that was the unsuccessful Irish challenger for the 1899 America's Cup against the United States defender, Columbia.

Shamrock was designed by third-generation Scottish boatbuilder, William Fife III, and built in 1898 by J. Thorneycroft & Co., at Church Wharf, Chiswick, for owner Sir Thomas Lipton of the Royal Ulster Yacht Club (and also of Lipton Tea fame).

[3] Shamrock featured a composite build, with manganese-bronze bottom and aluminium topside clinkerbuilt over a steel frame and a pine decking.

During her trials she raced against the 1895 America's Cup challenger, Valkyrie III, as well as twice beating the Prince of Wales yacht Britannia in regattas on the Solent.

She returned to Britain in the autumn of 1899, towed by Lipton's steam yacht, Erin.