Here's a quick and super easy DIY made from denim scrapes, especially useful for them pool days! :)
1. Cut out two rectangle sizes of denim (try it around your head to see if it is long enough to wrap around + tie at the back beforehand)
2. Place both the pieces in a criss cross, pull the pieces to create a link between them
3. Tie at the back, or if your pieces aren't long enough create holes at the ending and insert a smaller piece of cloth / ribbon to secure headband.