Cut a medium watermelon in half - you'll only need one half.
Remove rind from watermelon. Cut about 1/4 of the watermelon off and then cut into chunks. Set aside.
Juice the remaining 3/4 of the watermelon using a juicer. You can also use a blender and then strain the pulp.
Pull the smallest leaves from your mint sprigs and set aside. Chop the larger leaves as small as possible.
Combine 1/3 cup sugar and 3 oz light rum in a large mixing bowl and whisk together until sugar is about half dissolved.
Add watermelon juice, chopped mint, and lime juice. Whisk until well combined and sugar is fully dissolved.
Add 3-4 small pieces of watermelon (that you cut up and set aside earlier) to each freezer pop bag, along with 1-2 small mint leaves. Pour your watermelon mojito mix into the bag up to the fill line and seal. Repeat for the rest of your freezer pops.
Lay flat and freeze for 2-3 hours, or until solid.
Notes
Note: Nutrition information is a rough estimate only; actual values will vary based on the exact ingredients used and amount of recipe prepared.