Eucheuma cottonii is an carragenan seaweed which was used as gelling agent. The aim of this study were to observe the effect of Eucheuma cottonii addition as flat rice noodle's gelling agent and the influence of storage method on the flat rice noodle characteristics. Rice with different varieties (1R42, 1R64, and C4), tapioca flour with different concentration (0%, 5%, 10%, 15%, 20%, u 25% and 30% by the weight of rice flour), seaweed flour with different concentration (0%, 5%, 10%, 15%, 20%, 25%, and 30% by the total weight of rice flour and tapioca flour), and storage method (dry and frozen) were observed in this study. The results showed that the best flat rice noodle made from 28.6% IR64 rice flour (by the total weight of flat rice noodle dough) with 20% cassava flour addition (by the weight of rice flour) and 20% seaweed flour addition (by the total weight of rice flour and tapioca flour). The addition of 20% seaweed flour gave the best organoleptic acceptance (hedonic and scoring) and more chewiness than others. Frozen method gave better organoleptic acceptance (hedonic and scoring), chewiness, and microbial safety during storage rather than dry method.