clock clock iconcutlery cutlery iconflag flag iconfolder folder iconinstagram instagram iconpinterest pinterest iconfacebook facebook iconprint print iconsquares squares iconheart heart iconheart solid heart solid icon
Watermelon tuna poke bowl with veggies and fruits

Watermelon Tuna

  • Author: Liz Madsen
  • Total Time: 2 hours, 50 minutes
  • Yield: 4 cups 1x
  • Diet: Vegan


Watermelon Tuna is watermelon that’s marinated and baked in a savory brine that really makes it taste like sashimi-style vegan ahi tuna!


Units Scale
  • 6-7 cups seedless watermelon, diced or sliced (see 1st step for cutting suggestions)
  • 1/2 cup reduced sodium soy sauce or gluten-free tamari (if GF)
  • 3 tablespoons toasted sesame oil (see note 1)
  • 3 tablespoons neutral oil like avocado oil (see note 2)
  • 1/3 cup fresh squeezed lemon juice
  • 1 tablespoon dulse flakes, optional (see note 3)


  1. Start by slicing up your watermelon: I recommend using a seedless watermelon. Slice or chop the watermelon depending on what size and shape watermelon tuna you want. I like to dice it in 1 - 1 ½ inch cubes for a vegan tuna poke bowl, or in 1 ½ inch by 3 inch (ish) slabs (about ½ inch thick) for vegan nigiri. You could even do a mix of both. Either way, you’ll need about 6 or 7 cups of watermelon. Keep in mind that the watermelon does shrink a little during the baking process.
  2. Make the marinade: In a small bowl or measuring cup (I like to use a measuring cup since it has a spout), mix together the soy sauce, or gluten-free tamari, toasted sesame oil, neutral oil, fresh squeezed lemon juice, and the optional dulse flakes.
  3. Mix marinade with watermelon: Add the watermelon to a wide container. The wider the better because then the watermelon can spread out and get evenly coated with the marinade. Pour the marinade on top and mix gently. Cover and marinate for 3-4 hours. You can get away with as little as 2 hours or as many as 6 hours. After that the watermelon starts to deteriorate a bit.
  4. Prep for baking: After marinating, preheat the oven to 375 degrees Fahrenheit (190 degrees Celsius) and strain out the liquid (you can reuse this later if you’d like--it would also make a great tofu marinade if you wanted to prepare meals for the week!) and add the watermelon to a lined baking sheet in a single layer. Let each piece have a little space in between (around ½ an inch or more).
  5. Bake: Bake for 40-60 minutes--it kind of depends on how thinly you cut it! It should be a little darker, smaller, and it will be more tender when it’s done. I recommend letting it cool before serving--it tastes better at room temperature or chilled. It will soften a little in the fridge, though, so my favorite time to serve it is when it has just cooled to room temperature.
  6. Serve as desired: Serve as you’d like--in a poke bowl or a sushi bowl, in sushi burrito, in onigirazu (like a sushi sandwich), in vegan tuna sushi rolls (try making a spicy mayo from vegan mayo and sriracha), on top of rice as nigiri, etc. If you want to make the nigiri, watch a video online on how to shape it--that’s what I did, but I’m definitely not good enough at it to write instructions.
  7. Store: Refrigerate leftover watermelon tuna for up to 2-3 days in an airtight container. The texture softens a little in the fridge but it still tastes good for a few days afterword. Great in bowls!


  • Note 1: Toasted sesame oil really helps flavor the dish so I don’t recommend skipping it. If you can only find regular sesame oil, that’s OK, but it tastes better to use toasted or roasted sesame oil, so use that if you can find it (I usually get mine at Trader Joe’s or my local grocery store).
  • Note 2: We need a decent amount of oil to transform the texture of the watermelon. However, using all sesame oil is not only expensive, but I think the flavor would get too strong. So instead, I recommend using half sesame oil, half neutral flavored oil of your choice. I used avocado oil but other good options are grapeseed oil, safflower seed  oil, or even vegetable oil will work.
  • Note 3: Finally, for a little “fishy” flavor (but it’s not strong at all), I used a small amount of dulse flakes which I purchased online. You can substitute kelp granules or even a ripped up sheet of nori or two. Rip into tiny pieces and mix with the marinade.
  • Note 4: Want to use this to make a vegan tuna poke bowl? Start with a base of rice and add toppings. I like to use cucumber, shredded or grated carrots, edamame, green onion, mango or pineapple, avocado, pickled ginger, toasted sesame seeds, etc. If you want more info, check out my tofu poke bowl recipe.
  • Note 5: Making vegan tuna sushi or nigiri? Make some sushi rice and add vinegar, sugar, and salt -- let cool for about 1 hour and then it’s perfect for sushi use. For shaping and technique, I highly recommend watching some videos online. I have done this a little… but I don’t feel confident enough to instruct anyone on creating their own sushi or nigiri.
  • Prep Time: 5 minutes
  • Chill Time: 2 hours
  • Cook Time: 45 minutes
  • Category: Meat Replacement
  • Method: Baking
  • Cuisine: American, Asian

Keywords: Watermelon Tuna, vegan tuna, meat replacement