Ecological impacts caused by destruction of mangrove ecosystems results in loss of various species of mangrove flora and fauna. In the long run, it would disrupt the role of mangrove ecosystem. Therefore, degraded mangroves must be rehabilitated properly. For some years, guludan technique has been introduced to grow mangrove seedlings in the submerged area with deep water column. This technique has been applied in the mangrove area of Muara Angke Jakarta using Rhizophora mucronata seedlings with spacings of 0.25 m x 0.25 m, 0.5 m x 0.5 m, and 1 m x 1 m. Information on growh models and increments of the seedlings were quite important with respect to the assessment of performance and the success of the planting. This research was aimed at observing growths and increments of R. mucronata seedlings planted using guludan technique. Our obtained results showed that diameter growth model of 36 months planted seedlings of R. mucronata followed the logistic equation, while the height growth model followed the guludan equation. At the beginning of planting, spacing of 0.25 m x 0.25 m gave optimum diameter and height growths of the seedlings. Generally, wider spacing caused greater diameter growth, whereas denser spacing gave greater height growth