Blue crab

Blue crab may refer to:
 * Blue Crab 11, an American sailboat design
 * Callinectes sapidus – Chesapeake or Atlantic blue crab of the West Atlantic, introduced elsewhere
 * Cardisoma guanhumi – blue land crab of the West Atlantic
 * Discoplax celeste – blue land crab of Christmas Island
 * Paralithodes platypus – blue king crab of the North Pacific
 * Portunus pelagicus – blue swimmer crab of Australia and Southwest Pacific
 * Portunus segnis - a Western Indian Ocean species, was recently recorded in Tunisian waters, where it is invasive
 * Portunus trituberculatus – Japanese blue crab of the Northwest Pacific