The Roblox One Piece game that appears to have added Shamrock is Sailor Piece , based on current forum/game news mentions tied to the recent Shamrock-related buzz.

What looks most likely

  • The strongest match I found was Sailor Piece , since recent Roblox news pages are discussing its latest content and anime-inspired updates around the same time Shamrock started trending.
  • There is also a separate One Piece–style Roblox game called Haze Seas being discussed in recent videos, but I did not find a clear source saying it specifically added Shamrock.

Why there is some uncertainty

  • “Shamrock” is being used in multiple Roblox contexts right now, including Fisch and other games, so the name alone is not enough to pin down one exact title.
  • I did not find a direct, high-confidence patch note in the available results that explicitly says “Sailor Piece added Shamrock,” so this is the best match rather than a confirmed certainty.

Best read

If you mean a One Piece Roblox game , the answer is most likely Sailor Piece. TL;DR: Most likely Sailor Piece ; if you meant a different Roblox One Piece game, the Shamrock reference may be from a separate update or fan discussion.