Watermelon ‘Tuna’ Sashimi, the Plant-Based Catch
Nov 05, 2025
This post may contain affiliate links. Please read our disclosure policy.
This Vegan Watermelon Tuna Sashimi is the ultimate kitchen trick. Sweet, juicy watermelon turned into something that looks and tastes surprisingly like tuna! It’s light, refreshing, and perfect for impressing your friends at your next plant-based dinner or sushi night.
The watermelon really takes on the flavor of the marinade, making it taste just like tuna sashimi. Whether you’re looking for a new culinary adventure or just want to enjoy a healthier version of a classic dish, this Vegan dish is A++.
What is Vegan Sashimi?
Vegan Sashimi is made of thin slices of watermelon, marinated in a mixture of soy sauce, rice vinegar, and sesame oil. The watermelon takes on the flavor of the marinade, making it taste just like tuna sashimi.
What’s the Difference Between Sashimi and Sushi?
Sashimi is just thinly sliced raw fish (or another protein) served on its own, usually with soy sauce, wasabi, and pickled ginger. It focuses on the purity, texture, and flavor of the fish itself. There is no rice involved.
Sushi, on the other hand, always includes vinegared rice (called shari). It can be topped or rolled with fish, vegetables, or other ingredients. So while sashimi is all about the fish, sushi is about the harmony between rice and toppings.
How to Slice Watermelon for Sashimi
When slicing watermelon for sashimi, it’s important to use a sharp knife and to slice the fruit as thinly as possible. A mandoline slicer is the best tool for this job, but a sharp chef’s knife will also do the trick.
Thinly slice the watermelon into rectangles or triangles, being careful not to cut yourself. If using a mandoline slicer, use the thinnest setting possible.
Can Watermelon Sashimi Be Frozen
Watermelon Sashimi can be frozen, but I don’t recommend it. The texture of the watermelon will change when it’s frozen and thawed, making it less like tuna sashimi and more like a regular slice of watermelon.
If you do choose to freeze your sashimi, wrap it tightly in plastic wrap or place it in a freezer-safe container. When you’re ready to eat it, thaw it overnight in the fridge before enjoying.
Tips for Making this Recipe
- If you can’t find watermelon that’s ripe enough, leave it out on the counter for a day or two until it softens up.
- Ripe watermelons will have a dull sound when you tap on them and a uniform shape. Avoid watermelons that are misshapen or have a hollow sound.
- To ensure your watermelon is ripe, check the stem end for a honeydew-like scent.
- If you want to save time, you can buy pre-sliced watermelon at most grocery stores.
- For an extra special touch, garnish your sashimi with edible flowers.
How To Make Vegan Tuna Sashimi
Start by grating a ginger root. After skinning it with a spoon, finely grate it with a microplane.
Next, get out your watermelon. Cut it in half and remove pieces that are easy to slice. Cut your watermelon slices into sushi-sized pieces, about the shape and size of a domino. They should be about a half an inch thick.
Once you’ve sliced enough watermelon, it’s time to turn it into tuna! The secret is in the marinade. Add the ginger you just grated along with sesame seed oil and soy sauce. Put the watermelon in a plastic bag and pour the marinade over it, then put it in your fridge to let the marinade do its thing.
After a few hours, the watermelon slices will have absorbed a lot of the marinade. Now it’s time to give them that tuna texture. Pour both the marinade and the slices into boiling water in a stock pot and cook the slices until they’re tender. Remove them, let them cool, and roll them in a mix of black and white sesame seeds. They’ll look and feel just like tuna!
Want more from your watermelon? Check out these recipes:
- Watermelon S’mores
- Air-Fried Watermelon Bites
- Watermelon Pizza
- Grilled Watermelon and Italian Sausage Kabobs
- Watermelon and Cucumber Salad
- Watermelon Basil Margarita
Vegan Tuna Sashimi
Ingredients
- 4 cups seedless watermelon cut into ½” thick rectangles
- ½ cup soy sauce
- 1 tsp toasted sesame oil
- 1 tsp black sesame seeds
- 1 tsp white sesame seeds
- ½ tsp fresh grated ginger from 1 ginger root
Instructions
- Peel ginger root with a spoon and grate with a microplane.
- Cut watermelon slices into ½” thick rectangles.
- Mix together toasted sesame seed oil, soy sauce, and grated ginger to form marinade.
- Marinate watermelon pieces for about 4 hours.
- Bring water to a boil in a stock pot and add watermelon and marinade. Cook for about 10-15 minutes. The pieces should all be very soft.
- Mix black and white sesame seeds in a ramekin or small dish.
- Drain and turn “sashimi” watermelon slices in sesame seeds on four sides.
- Serve with some cucumber slices, sriracha mayo, and spring onions and enjoy!
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
