The coastal area is sub-optimal land which is poor in nutrients. Therefore it is necessary to add organic matter to increase nutrients content. The research that has been conducted aims to determine the effect of seaweed compost and biochar application on soybean growth on sandy coastal soils. The research was arranged in a Completely Randomized Design consisting of two factors. The first factor was the dose of seaweed compost, namely 0, 20, 40, 60. The second factor was giving biochar, namely without biochar and giving biochar. The research data were analyzed using Analysis of Variance, if there was a significant difference, it was tested with the Duncans Multiple Range test at the 5% level. The results showed that the interaction between seaweed compost and biochar significantly increased the growth rate of plant height. Biochar significantly increased plant dry weight and pod number. Seaweed compost only significantly increased root dry weight. The number of nodules, root length, and harvest index were not affected by seaweed compost and biochar.