To a small saucepan, add the water and sugar.
Heat over medium heat and bring the mixture to a simmer.
Add in the lychees and give it a stir, pressing lightly on the fruit. (Note: lychees will release additional liquid).
Let the syrup reduce and thicken, stirring occasionally, until it can lightly coat the back of a spoon (with a consistency similar to maple syrup).
Pour the syrup along with the lychees into a jar, and let cool.
Once cool, place the syrup into the fridge for 1 hour to let the flavour from the lychees permeate the syrup.
Pour the cooled lychee syrup through a sieve into a clean glass jar (press lightly on the lychees to extract their juice). Use a funnel if transferring into a small opening. (You can discard the lychees, or eat them -- however, they may be a little sweet. I like throwing them into a smoothie).
Use as you would in flavouring drinks or desserts.
Store the syrup in the fridge for up to 1 week.