Rubuta ci gaba don wannan sakin layi - A 2015, Serena Williams ta yanke shawarar fara kakar wasan ta a taron baje kolin a Perth, a gasar cin kofin Hopman
Haɗuwa da John Isner, sun yi rashin nasara a wasan karshe na Poland Agnieszka Radwańska da Jerzy Janowicz. A gasar Australian Open, Williams ta lashe lambar yabo ta 19 ta doke Maria Sharapova, inda ta sanya ta ta biyu a cikin mafi yawan slams da aka ci nasara a Open Era. Williams ta kawo karshen shekaru 14 na kauracewa BNP Paribas Open amma ta janye kafin wasan kusa da karshe. Daga nan sai ta yi ikirarin lashe lambar yabo ta takwas ta Miami Open da ta doke Carla Suárez Navarro a cikin minti 56 kawai a wasan karshe bayan da ta lashe wasan kusa da na karshe da aka yi da Simona Halep. Daga nan sai ta kai wasan karshe na French Open kuma ta yi ikirarin nasarar ta ta 20 da ta doke Lucie Šafářová a cikin saiti uku, ta zama mutum na biyu da ya lashe kowane slam sau uku. Ta goyi bayanta ta hanyar lashe taken ta na 6 na Wimbledon a kan Garbiñe Muguruza don zama mutum na farko da ya lashe Slams uku sau shida kuma dan wasa na farko tun Steffi Graf da ya lashe Slams uku na farko na shekara. Williams ya dawo daga raunin gwiwar hannu a Toronto amma ya yi mamakin matashiyar 'yar Switzerland Belinda Bencic a wasan kusa da na karshe. Daga nan sai ta yi ikirarin taken ta na biyar na shekara a Western & Southern Open ta doke Simona Halep. A US Open, Williams na da damar lashe Grand Slam na kalanda amma Roberta Vinci ta yi masa rauni a cikin wasanni uku a wasan kusa da na karshe. Williams ita ce zakara mai karewa sau uku, amma a ranar 2 ga Oktoba, Williams ta janye daga gasar don warkar da raunin da ta ji da kuma dawo da motsawar ta.