Traveling south from Route 104 brings Trainers to a rocky sea with six small islands along the western side of the route, one of the islands containing the Island Cave. Trainers who wish to visit the Island Cave cannot Surf straight to it due to a rocky barrier around the small island, and will have to navigate south to cross the largest sand isle; containing a small forest and Ruin Maniac Foster pacing back and forth. In Emerald, west of that isle holds a Double Battle with Bird Keeper Josue and Ruin Maniac Andres and a hidden Big Pearl.
In Sharpedo Attack!, the group continued to travel along Route 105, eventually stopping for a break on an unnamed crescent-shaped island that Mr. Briney found during his earlier sea voyages. Suddenly, a school of Sharpedo surrounded the S.S. Wingull and began ramming into it. After Pikachu shocked the horde, Mr. Briney was able to dock the ship on the island. After isolating the Sharpedo leader, Brock sent Lotad out to battle it.
Brock then realized that Sharpedo was severely poisoned, and began to nurse it back to health despite having no medical supplies. Team Rocket appeared the next day in their Magikarp submarine and netted the Sharpedo, revealing that Jessie's Seviper had poisoned Sharpedo. After Lotad helped free Sharpedo, the rest of the school sent Team Rocket blasting off. With the Sharpedo now friendly towards them, Mr. Briney and the others were able to reach Dewford Island that same evening.
Route 105 first appeared in Tongue-Tied Kecleon, where Ruby led Wally to its edge in Petalburg Woods. There, he helped Wally catch his very first Pokémon, a Kecleon. However, the area was then struck by a sudden earthquake and a tsunami, which knocked Wally unconcious and caused Ruby to be washed into the sea, from which he was later picked up by Mr. Briney on his boat.