After you fight Zinzolin in Lacunosa Town and go west through Route 12, you reach Village Bridge.
Explore Town
There is no pokémon center here, but in the first house to the left, there is a woman with a Gothorita who will heal up your pokémon.
If you go south from the Route 12 gate, you find two Smashers (tennis players) running up and down. They are Smasher Lizzy, who has a level 44 Whimsicott, and Smasher Amy, who has a level 44 Liligant.
In the northwest corner of the tennis court, there is a Carbos next to a bench.
If you go west from the tennis court, then north and under the bridge, you find Artist Gough, who has a level 42 Sunflora.
Northeast of the artist, use your Dowsing Machine to find a hidden Big Mushroom. Go to the east to find a Rare Candy out in the open. You can also talk to the musician (Derleth) to add a new melody to the background music.
You can Surf west and north from the from the painter to find a small island that has a Big Pearl on it. Surf west from there and get the Blue Shard in the corner of the fence.
South of there, there is an island in the middle of the bridge where you find Fisherman Dean, who has a level 42 Basculin. There is a Heart Scale next to him.
Go south under the bridge on the west side and look at the wall to the left. There is a hard-to-see door. Go through to find a girl who is singing. She tells you that she's practicing, and she kicks you out. You can talk to the guy outside near the trash can (Koontz) to add his singing voice to the background music.
To the west, get the Ultra Ball from the grass. You can fight Youngster Karl nearby. He has a level 42 Sandslash. Use your Dowsing Machine in this area to find a Max Ether.
Go west and north from the youngster to find a guitarist (Aickman) near a vending machine. Talk to the guitarist to add the guitar to the background music. Check the trash can nearby to get a PP Up. To the right, there is Hoopster Nicolas who has a two level 42 Magbys and a level 42 Magmar. He challenges you to a triple battle. There is also Hoopster Derrick also challenges you to a triple battle, but he has two level 42 Elekids and a level 42 Electabuzz.
You can go east on the bridge and into one of the houses to find Baker Chris, who challenges you to a battle with her level 42 Heatmor.
If you go farther east on the bridge, there's a bald guy you can talk to (Russo) if you want to add some beatboxing to the background music. South of the bald guy, talk to the girl. If you found the girl who was secretly practicing singing, the bridge girl will give you Sitrus Berries.
Farther east, Gentleman Stonewall blocks your path. You have to defeat his level 43 Durant and level 43 Lucario before he will let you pass. But as you have already seen, you can just Surf under the bridge. Fight him if you want to.
Otherwise, you can go west to leave Village Bridge and reach Route 11.