Umai refers to the indigenous dish from Sarawak and Sabah in Indonesia. It is their own version of the famous Ceviche, as it is made of raw mackerel seasoned with chopped onions, chili peppers and salt and uses lime juice instead of vinegar as a souring agent.
Umai is Indonesia's version of the Philippines, Kinilaw na Isda, which is prepared almost the same way.