Can I find all mini medals later in the game?

Scattered around the world are treasure chests with mini medals in them. I think you can turn them in later in the game for some cool swag, but I've missed a few on my own.

I'm going to keep going forward in the story until fast traveling becomes easier so I'm wondering if I'll miss out on any mini medals that I didn't get in past areas because I'm too forward in the game's story.

Solution 1:

You are able to farm all of the mini medals in act 3. There is also a source to abuse for infinite medals. I believe there are 110 medals in total, but as I just mentioned you can collect more than that.