The water availability in tidal swamp land type C is similar to the rain-fed area. However, waterlogging may occur if the irrigation system is not good. This experiment aimed to study the effect of different planting dates in growth, yield, and phenology of different soybean lines grown under tidal swamp land. A randomized complete block design was repeated four times, each planting date differed 46 days apart. Interaction of genotype and planting date were demonstrated by days to flowering and days to maturity. Different response on days to flowering and days to maturity showed that the tested genotypes had phenological adaptation on a particular planting date. No interaction was shown by other agronomical traits, even though the genotypes were significantly different. Most of the lines had similar seed yield to the control varieties. The genotype of Menyapa (G12) had the largest number of filled pods, but the seed size was the smallest. Consequently, the seed yield of G12 was lower than the genotypes with the slightly lower number of filled pods and larger seed size. The shortest maturity genotypes of Tgm/Brg-584 (G10) also showed similar seed yield to the control varieties. Seed size is substantially responsible for the performance of seed yield. The most promising lines was Snb/1087-148-2-1 (G4), because this line had high yield and large seed size. Interaction in phenological response reflecting in days to flowering and days to maturity was not followed by agronomical traits suggesting that the effect of phenological traits to agronomical traits is weak. Therefore, the soybean promising lines can be grown at those two planting dates.