Combine water, sugar, and sliced peaches in a medium saucepan over medium-high heat and bring to a boil.
Once boiling, lower heat and let simmer for about 15 minutes, until mixture has thickened and peaches have softened.
Strain mixture into a bowl, being sure to press down on the peaches to extract as much juice as possible.
Keep syrup in bowl or pour into a mason jar and place in fridge to cool completely before using. Syrup will continue to thicken as it cools.