Reduction of the quantity and quality of forage is one of the main restrictions on the productivity of livestock systems. Tropical legumes are the most important crops to improve livestock feeds and, thus, for providing livestock products for human consumption in arid regions. In order to investigate the shift of cultivation date of two legumes from summer to spring in arid weather conditions, a factorial experiment in a randomized complete block design with three replication was conducted at the Agricultural Research Institute of south Kerman, Iran, during two cropping seasons. Treatment was planting in three and two tropical legumes (Tapary bean and cowpea). The results showed that changing planting dates led to a significant effect on seed yield and forage quality of two legumes in the region. All agronomic traits for cowpea increased compared to Tepary bean due to differences in their genetic backgrounds. The two legumes were not different in terms of nitrogen, crude protein, and ash. On all three planting dates, the hemicellulose-free cell wall of cowpea was higher than Tepary. In contrast, neutral detergent fiber for Tepary was observed more than cowpea. The highest dry matter index was recorded for cowpea. Whereas the highest dry matter digestibility, the net energy of lactation, and metabolizable energy were related for Tepary. According to the different physiological and phenological responses of the two legumes, it is necessary to examine the selection of suitable planting dates for improving the quantitative and qualitative yield of forage.