Follow the visible path on the ground beyond the grass to encounter yet another martial artist.

Battle: Battle Girl Alize (1312 Poke)
Opponent: Scrafty Lv 41

Continue North and then West until you reach the stairs down to the beach- but before you descend, head South and chop down a little tree.  Behind it lies another Max Repel.  Return to the stairs, step onto the sand, then head North just far enough to retrace the beach without passing the water.  You’ll first encounter an Ace Trainer wading back and forth in the saltwater.

Battle: Ace Trainer Miguel (2460 Poke)
Opponent: Delcatty (Female) Lv 41, Eelektrik Lv 41

Continue past him to find a Heart Scale left of a large rock in the sand, hidden in the ground.  To the right of the rock is an obvious Item Ball, containing an Ultra Ball.  Keep going as far as you can and you’ll encounter a Fisherman staring at some rocks.

Battle: Fisherman Leroy (1280 Poke)
Opponent: Vaporeon Lv 40

From here you can leap down a ledge to the first portion of the route if you like, but it takes no less time to return to where you turned back around either way, so just head back to the West.

When you reach the stairs that brought you down onto the sand, continue to the West and a touch South so you can climb the tall stairway.   Grab a Zinc from the smaller open patch on the edge of the tall grass, then head North.  You’ll soon come across a Strength boulder, which should be shoved North into the hole.  This allows you to grab the Red Shard behind it, and then return to the beach stairs a second time.