Airlines that charge for a second bag

[Dragon Eye]

This is the bag we traveled with: 

I was 1 surprised to be able to fit all the gear in here, much less two people's gear (small woman, xl man- the men's fins were a squeeze but worked). 2 was really glad with the way it held up for the two flights and cruise handling! Nothing broken not even a zipper- it's a tough bag.

You could probably pack all your clothes and scuba gear in this one bag (I forgot to mention we took the large mesh bag and stuffed it in for when we got to our destination).  Just have to keep the weight in check.