What does watermelon tuna taste like?

Watermelon tuna doesn’t actually taste like fish—but when seared, it takes on a tender, sashimi-like appearance. The edges caramelize, the center softens, and the ponzu, ginger, and smoked salt bring out a savory, slightly briny flavor. Think bright, smoky, and refreshing rather than fishy.

Can you make watermelon tuna ahead of time?

Yes—you can slice and chill it up to a day in advance, and it will hold up for sushi night or a poke bowl. Just know the texture softens slightly the longer it sits, so for the best sashimi-like bite, sear and serve the same day.

Does watermelon really work as vegan tuna?

It does—and that’s the fun of it. When seared, watermelon loses its sugary edge and transforms into something tender, savory, and a little smoky, with a texture that mimics sashimi. Paired with soy sauce, ponzu, or wasabi, it delivers that sushi-night experience without the fish.

Watermelon Tuna | Olives for Dinner

Ingredients

For the Watermelon

4 slabs seedless watermelon, about 4 inches long × 1 inch thick, patted dry
2 tablespoons olive oil

To Serve

4 teaspoons ponzu sauce (check ingredients to ensure it’s vegan)
1 teaspoon freshly grated ginger
A few pinches smoked salt
Microgreens or chopped scallions, for garnish
Soy sauce or tamari, for dipping

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Instructions

Preheat the olive oil in a large cast-iron skillet over medium-high heat for 2–3 minutes (reduce heat if the oil begins to smoke).
Place the watermelon slabs into the skillet carefully—expect a little sputtering as the fruit hits the hot oil. If there’s a lot of sputtering, reduce the heat slightly.
Sear on one side for about 3 minutes, or until golden and caramelized, pressing gently with a spatula. Flip and sear the other sides for 2–3 minutes more, until all surfaces have a nice sear.
Transfer the seared watermelon to a cutting board and let cool slightly. Slice into ¼-inch thick pieces and arrange on plates.
Combine ponzu and grated ginger, then drizzle evenly over the slices. Sprinkle with smoked salt, garnish with microgreens or scallions, and serve with soy sauce for dipping.

Notes

Watermelon Prep: Use seedless watermelon for best results. Even slabs (about 1-inch thick) sear evenly and slice neatly for sashimi-style pieces.
Make Ahead: Seared watermelon tuna can be sliced and chilled up to a day in advance. Serve cold for sashimi-style sushi night or let it come to room temp before plating.
Serving Ideas: Enjoy as vegan sashimi with soy sauce, layer onto sushi rice, or add it to poke bowls. It also works as a fun appetizer with microgreens and ponzu.
Substitutions: If you can’t find ponzu, mix soy sauce with a splash of lime juice for similar brightness. Flaky sea salt can stand in for smoked salt if needed.
Storage: Leftovers keep in a covered container in the fridge for 1–2 days. The texture softens, but the flavor stays bold.

Author: erin wysocarski
Prep Time: 5 minutes
Cook Time: 15 minutes
Category: Vegan Seafood
Method: Seared
Cuisine: Japanese-Inspired
Diet: Vegan