Who might Harry meet while he is on a ship in a fanfic?

There's a chance he'll run into Ron. Maybe Ron is looking for some new wizarding sweets at Honeydukes, and they end up sharing some of the treats while they continue their shopping spree. And it's possible that they'll see Neville there too, who is searching for some rare plant seeds for his Herbology studies.

Ron and Hermione are the most likely ones. They are his best friends and have always been by his side through thick and thin. They would probably follow him without hesitation and use their own skills, like Hermione's vast knowledge and Ron's loyalty and practical skills, to assist in the ship - stealing adventure.

He could meet Hagrid. Hagrid often goes to Diagon Alley, so it's possible he'll run into Harry while he's shopping and give him some useful advice about what to buy or not to buy.

He could meet centaurs. Centaurs are known to live in the Forbidden Forest in the Harry Potter universe, and if Harry is living in the woods, it's very likely he'd cross paths with them. They might teach him about astronomy and prophecy in a more in - depth way than he learned at Hogwarts.

Perhaps he'll meet an old patient who has been in the hospital for a long time. This patient could tell Harry some long - forgotten stories about Hogwarts in the past. There could also be a chance that he meets some other students who are also in the hospital for various reasons, and they might form a new friendship or alliance.

Perhaps he'll meet some interesting magical creatures that are native to the holiday location. It could be a friendly forest sprite or a wise old centaur. He may also cross paths with some international wizards who are also vacationing there and learn about different magical cultures from them.

He could meet some of the Hogwarts ghosts. They might have some interesting stories or information about the wards that could help Harry in his task.

Dumbledore might make an appearance. He could come to give Harry some advice or to share some important information about the war against Voldemort. Dumbledore might also be interested in seeing how Harry is faring in the old Black family house and if he's discovered anything of significance there.

He could meet the castle guards. They might be suspicious of him at first but then become friendly as they realize he has no bad intentions.

He might meet the house - elves that have been taking care of Potter Manor for generations. They could show him around the manor and tell him stories about his family.