Bring 500 ml of water to just under boiling (about 90°C / 194°F). Remove from heat and steep 2 green tea bags for 2.5–3 minutes for a mild, slightly grassy brew. Remove tea bags and allow tea to cool to room temperature (about 15–20 minutes) or chill briefly in the refrigerator.

Make watermelon purée

Place 4 cups of cubed seedless watermelon in a blender. Blend on high until smooth, about 30–45 seconds. If you prefer a silky texture, pass the purée through a fine mesh strainer into a bowl, pressing with a spoon to extract as much liquid as possible (optional). You should have roughly 2 to 2.5 cups of watermelon juice.

Combine cooled green tea and watermelon purée in a large pitcher. Stir to combine and add 250 ml cold water to adjust intensity if needed.

Citrus, Sweetener & Seasoning

Add 60 ml fresh lemon juice and 15 ml fresh lime juice to the pitcher with the tea–watermelon mixture. Taste and then stir in 45 ml simple syrup (or honey syrup) to reach your preferred sweetness level.

Add 1 teaspoon salt to brighten flavors. Stir thoroughly and taste; adjust lemon, syrup, or salt as desired.

Garnish & Serve

Fill four serving glasses with ice (about 1/2 cup ice per glass). Divide the watermelon green tea mixture among the glasses (about 1 cup per glass).

Garnish each glass with a thin lemon slice and 1–2 fresh mint leaves. Serve immediately chilled.