The Straw Hat Pirates reunite in episode 517 of the One Piece anime, titled "A New Chapter Begins - The Straw Hat Crew Reunites!". This episode marks the end of a two-year separation period, during which each member of the crew embarked on an individual journey to become stronger and more skilled. During this time, the Straw Hats underwent rigorous training, honing their abilities and expanding their horizons in preparation for the challenges of the New World.