In a small saucepan over medium heat, stir sugar into water until dissolved into a simple syrup.

Set aside to cool.

In a large bowl or pitcher, combine grapefruit juice, lime juice, tequila and sea salt; add simple syrup and stir.

Pour carefully into popsicle molds.

Freeze 1 hour before inserting popsicle sticks into molds.

Freeze 12 hours total before serving (less if you swap tequila for water or club soda).