Sperm becomes capable of movement while in the epididymis.
The epididymis is a tube in the male reproductive system that connects a testicle to a vas deferens. Its function is to store immature sperm cells for 2–3 months. During their time in the epididymis, sperm undergoes maturation processes where they get the ability to swim forward (motility) and ability to fertilize an egg. Final maturation is completed in the female reproductive tract.
