Place the uncooked sushi rice into the inner pot of a rice cooker. Wash the rice 3-4 times and drain well.
Add 3 cups of water into the same pot, or fill the pot until it reaches the line marking for 3 cups of sushi rice. If you do not own a rice cooker, you may cook it on the stovetop or use an Instant Pot.
While the rice is cooking, combine the rice vinegar ingredients and mix until the sugar and sea salt are dissolved.
After the rice is cooked, transfer it into a large mixing bowl. Immediately pour the vinegar onto the rice and fold the vinegar into the rice with a rice paddle until evenly distributed.
Cover the mixing bowl with a damp cloth or towel until the rice is cooled to room temperature. It is now ready to be used for sushi!