Planting date and soybean cultivar choice significantly impact soybean yield and plant characteristics. A study in Iran found that planting on May 10th resulted in the tallest plants and highest seed and biological yields. The Williams cultivar outperformed others in terms of pod number, seed weight, and overall yield. The best combination for high seed yield was planting on May 10th with the Williams cultivar, resulting in a yield of 3107 kg/ha. This research suggests that May 10th is the optimal planting date and Williams is the best cultivar for soybean production in the Ilam region.