Warning: Contains spoilers for One Piece volume 101.
What did the Straw Hat pirates get up to during the One Piece's time skip episode? While the specific details haven't been explored at this point, One Piece's time skip still changed the status quo of the series and worked to establish how all of the Straw Hat Pirates would act for the rest of the series. This is everything that they did during that time and how the time skip might factor into the upcoming One Piece movie, One Piece Film: Red.
So when is the time skip in One Piece? It takes place in episode 517. After the Straw Hat Pirates were separated at Sabaody Archipelago, Luffy moved to save his brother Ace from execution rather than try to reunite with them. Luffy threw himself into both Impel Down and the Paramount War of Marineford to try and save Ace, but in the end, Ace ended up killed by Admiral Akainu. The entire experience made One Piece's Luffy realize that he and his crew were still far too weak to take on the challenges of the New World, so Luffy sent a coded message to the Straw Hats via the newspaper that they were to reunite on Sabaody in two years.
Related: How Netflix's One Piece Has Changed 3 Major Ships
Luffy's message of reuniting on the Sabaody Archipelago in two years is what kickstarted the One Piece time skip, and this is what all Straw Hat Pirates did during that time. Once again, the specifics of what the Straw Hats did during the time skip haven't been fully explored, but new details about their activities have been revealed periodically over the years, even in the current Wano arc. As such, everything here is a compilation of what's known about the training they did during the time skip at this point.
The One Piece anime's time skip
Read more on screenrant.com