Mix the coconut rum, pineapple juice, orange juice, and lime juice in a large punch bowl.
Add the grenadine and stir until well combined.
Place the fresh pineapple chunks, orange slices, and lime slices in the punch bowl.
Add ice cubes to keep the drink cold.
Pour in the club soda right before serving and give a gentle stir.
Serve in glasses filled with ice and garnish with fruit pieces and cherries if desired.
Notes
Store any leftover punch without ice in the refrigerator for up to 2 days.Replace club soda with ginger ale for extra sweetness.Make ice cubes with pineapple juice to prevent the punch from getting watery.For a stronger drink, add an extra cup of rum.For a non-alcoholic version, skip the rum and add more club soda.