After you get the Relic Badge from the Hearthome Gym, you can Surf through Route 218.

Explore the Route

If you fish in this route with the Old Rod, you can catch Magikarp. If you fish with the Good Rod, you can catch Magikarp and Finneon. While Surfing in this route, you can encounter Pelipper, Tentacool, Tentacruel, and Wingull.

Check on the water to Surf in it. If you go northeast, you find a Rare Candy.

Go southwest in the water to find a jar of Honey. To the north, you can battle Fisher Miguel, who has two level 29 Gyarados. You get 1160 Pokédollars for winning.

North of Fisher Miguel, you can battle Fisher Luc, who has four level 26 Magikarps and a level 31 Gyarados. You get 1040 Pokédollars for winning.

To the west, you can battle Sailor Skyler, who has a level 27 Mantyke and a level 31 Gyarados. You get 1240 Pokédollars for winning.

Talk to the camper to the south to get 3 Flora Stickers F.

Near the camper, you can battle Guitarist Tony, who has a level 31 Luxio. You get 992 Pokédollars for winning.

In the grass, you can catch Floatzel, Gastrodon, Glameow (Shining Pearl only), Mr. Mime (Brilliant Diamond only), Shellos, and Wingull.

To the east of the guitarist, there are Berry Trees.

Go west to reach Canalave City.