Surf is perhaps one of the most important hidden moves that you obtain in Pokemon Brilliant Diamond and Shining Pearl. This handy hidden move is necessary to travel across the oceans and get around some areas like the lakes. You really can’t beat the game without it. Luckily, it is easy to obtain. Here is where to find this important TM.
During the game, you will run into an NPC named Cynthia. She will help you out in certain situations. Once you reach Pastoria City and defeat the gym leader there, Cynthia will appear and give you the medicine needed to help the Psyduck’s on Route 10. She will appear again when after you heal them to ask you to take the Old Charm to her grandmother in Celestic Town.
After a long trek across Route 10, you will meet Cynthia’s Grandmother. She will inform you that there is a “spaceman” in front of the ruins. Defeat the man and grandma will tell you to search the ruins. After walking inside, grandma will come in and give you the Surf TM. You won’t be able to use it just yet, however. First, you will need to make your way to Hearthome City and defeat the gym leader. Once that is done, you will be on your way to surfing across the wide-open ocean.