Removing secondary branch to produce commodity watermelons is labor-costing and time-consuming work in traditional watermelon cultivation. Moreover, because elderly farmers work for a long time with their backs bent, musculoskeletal disorders reduce the quality of life of farmers. To improve this working condition, we developed the watermelon 'Soonless' variety that does not need to be pruned because there is no secondary branch. For diploid oval watermelons, the stripe width of the fruit is wide, the color of it's skin is green, and the flesh is pinkish-red. It contains 480 seeds of ‘Soonless’, and the fruit weight is 8.6 kg, which is heavier compared to ‘Sambokggul’. The thickness of the pericarp is 1.3 cm, and the total soluble solids content is 12.0 °Bx, which is similar to ‘Sambokggul’. The characteristics which distinguish it from the control variety include the leaf blade length and width, the ovary size, the width of the fruit stripes, and the thickness of the pericarp. The yield was 6,450 kg/10a, an increase of 5.3% compared to ‘Sambokggul’. As a result of this research, ‘Soonless’ has been registered as a variety with the Korea Seed and Varieties Service in 2022 as it was filed for breed protection in 2019 (Registration No. 8808).