Where do you find each of the pouch expansions?

Solution 1:

There are six in total that you can find (one for each party member throughout the game). Here is where you get each of them:

1. You'll receive this one in the main story during chapter 2 from

killing Dughall.

2. You'll receive this one in the main story during chapter 6 from

killing Giga Rosa.

3. After the story event in the bandit cave in Gormott, you'll find this in a chest.

4. When you've been to Leftheria, you can skip travel to Godford Isle, turn around and drop onto the moving platform. It will pass by one platform that has a collection node, but when you go farther north you'll find another platform with a chest on it containing the 4th expansion.

5. At the end of Spirit Crucible Elpys (in the Vault of Heroes area, underneath the staircase), you can find the 5th expansion. This one will require a skill check.

6. When you can access the Beruf Industry Ward in Mor Ardain (NE, Alba Cavanich) you can ride a moving cargo container to a cliff off to the side. There is a key obtained by doing the quest We Meet Again which is required to access the factory.

source

Why are there 6 instead of 5 (the number of party slots you have)?

Vandham dies, so just in case you used one on him, you can still get an additional one later.