Blend about 4 cups of chunked fresh watermelon in a high-speed blender until smooth, about 2-3 minutes.

Strain the blended watermelon juice through a fine mesh sieve into a large bowl to remove pulp and foam.

Pour 1 cup of fresh watermelon juice into a small saucepan and heat over low heat. Sprinkle unflavored gelatin powder over the remaining juice in a bowl and let it bloom for 5-10 minutes.

Gently warm the juice in the saucepan for about 3-5 minutes without boiling.

Whisk the bloomed gelatin into the warm juice mixture until fully dissolved and smooth.

Stir in freshly squeezed lemon juice and honey (if using) until well combined.

Pour the gelatin mixture into gummy molds or a glass dish; let sit for 5-10 minutes at room temperature.

Refrigerate for at least 2 hours or until completely set.

Carefully remove gummies from molds or cut into shapes if using a glass dish.