Combine the sliced peaches, honey, and water in a large saucepan and heat gently over medium-low heat, stirring occasionally, just until the peaches soften and release aroma without breaking down completely or boiling aggressively; remove from heat, add the lemon zest, cover, and let steep for about 10 minutes, then strain through a fine-mesh sieve without pressing the solids and allow the syrup to cool completely.
Add the lemon pulp to a large pitcher and gently muddle it just enough to release juice and light texture without turning it into purée.
Pour the cooled peach–honey syrup into the pitcher with the lemon pulp, add the fine sea salt, and stir to combine, then add the ice-cold water and mix gently until fully integrated; taste and adjust only with additional cold water if needed — sweetness and acidity should already be in balance.
Refrigerate for 1–2 hours until fully cold and the flavors are fully aligned.
Fill glasses with ice, pour over the peach lemonade, and garnish with lemon slices and fresh peach slices.
