Walkthrough: After participating in your first Battle Royal, you can continue your Island Challenge by heading on Route 7. This Route connects to both Route 8 and Wela Volcano Park, the latter being the location of your next Island Trial.
Wild Pokemon:
Surfing (Levels 16-19): Finneon(30%), Tentacool(30%), Pyukumuku(20%), Wingull(20%)
Fishing (Levels 10-19): Magikarp(79%), Wishiwashi(20%), Staryu(1%)
SOS Pokemon #1 (Levels 10-19): Gyarados, Wishiwashi, Starmie
SOS Pokemon #2 (Levels 10-19): Gyarados, Wishiwashi, Staryu
SOS Pokemon #3 (Levels 10-19): Magikarp, Wishiwashi, Staryu
Fishing Bubble Spots (Levels 10-19): Magikarp(60%), Staryu (20%), Wishiwashi(20%)
SOS Pokemon #1 (Levels 10-19): Magikarp, Starmie, Wishiwashi
SOS Pokemon #2 (Levels 10-19): Magikarp, Staryu, Wishiwashi
SOS Pokemon #3 (Levels 10-19): Gyarados, Staryu, Wishiwashi
Rustling Spots (Levels 16-19): Diglett(100%)
Zygarde Cells: There is one Zygarde Cells found here.
Trainers:
Swimmer Dakota - Level 19 Surskit, Level 19 Dewpider
Swimmer Tiare - Level 19 Alomomola
Swimmer Casey - Level 19 Mareanie
Swimmer Vanessa - Level 18 Shellder, Level 19 Corsola
Items:
Max Repel - Northern Beach
Antidote - Northeast Underwater
Net Ball - Southern Beach (Hidden)
Pearl - Near Bottom of Beach (Hidden)
TM73 Thunder Wave - On Mini Island Off Coast