Start by peeling and pitting the fresh lychees.

In a large saucepan, combine the water and sugar over medium heat. Stir until the sugar dissolves completely, creating a simple syrup.

Add the prepared lychees to the syrup, and simmer for about 5 minutes.

Remove the saucepan from heat and let the mixture cool to room temperature.

Once cooled, pour the lychee syrup mixture into a blender. Blend until smooth.

Using a fine mesh strainer, strain the blended mixture into a clean bowl.

Add the vodka and fresh lemon juice to the strained lychee syrup. Stir well to combine.

Transfer the liqueur into glass bottles and seal tightly. Refrigerate for at least a few hours.