Bottle 1: If you help Medli fly across the gap in Dragon Roost Island she will give you a bottle.

Bottle 2: Go to Rock Spire Isle and, board not raid, board the ship and you can buy your second bottle there.

Bottle 3: If you defeat the enemies in the submarine in Bomb Island you will get a bottle for defeating them.

Bottle 4: After you rescue the girls from the Forsaken Fortress you can find the former rich girl trying to crack into the safe that belongs to Zunari. Talk to her and she will tell you to go away, go to the stair behind the shop and she will run the other way. Every few steps she will check if anyones stalking following her. If you aren’t hidden she will run away and you’ll have to start over, if your partly hidden then Link will meow like a cat. Once you follow her back catch her in the act, she will ask you some questions. Chose the first one the whole time. The bottle is yours!