Narrow-barred Spanish mackerel (Scomberomorus spp.) is a species of fish that is widely preferred due to its high potential and economical value. This research is aimed to utilize seaweed (Eucheuma cottonii and Eucheuma spinosum) to increase iodine and dietary fiber content of fish meatballs to help fulfill the daily needs of Indonesians. The first stage of this research was conducted to determine the best type and concentration of seaweed flour to be added to the fish meatballs dough. A series of seaweed flour addition concentration employed in this research are 1, 2, 3, 4, and 5% for each type of seaweed separately. Several factors put into consideration when selecting the best seaweed addition concentration were moisture content, texture, and organoleptic tests (scoring and hedonic). Through moisture content, gel strength, and organoleptic analysis, 2% Eucheuma cottonii was chosen to be added. Second stage of this research was conducted to compare the chosen meatball with control. The chosen fish meatball has better profile of moisture, fat, ash, carbohydrate, dietary fiber, and iodine content compared to control. Dietary fiber and iodine content analysis showed that the chosen fish meatball contain 0.0046% dietary fiber and 102 mcg/100g iodine.