The port is the only one on Greed Island and it is the location where the unscrupulous Harbormaster is. Although it is a port, the player does not leave the island transported by a boat or ship, but rather through teleportation done by the Game Master Elena from a tower in the port city.
Greed Island arc
Gon, Killua, and Biscuit come to this port and Killua defeats the Harbormaster, transforming him into the "Transport Ticket". Immediately Killua uses it to leave the island and Gon and Biscuit continue their training while heading back to Masadora.
After winning the game, List and Dwun tell Gon to choose his three prize cards and go to the port. There, Elena transports Gon out of the game and ponders if what she did was the right thing to do; a flashback reveals that Ging instructed Elena that if Gon takes a "Magnetic Force" card she should send Gon to see him when he uses the card, but if he takes an "Accompany" card then she should send him to Kite.