The 20-year-old was handed several first-team opportunities at Liverpool during their defensive injury crisis last term, making 19 appearances under Jurgen Klopp across all competitions.
However, Ibrahima Konate's signing - as well as the returns to fitness of Virgil van Dijk, Joe Gomez and Joel Matip - have limited Williams's prospects of first-team action in the 2021-22 season so far.
The centre-back has been tipped to join Swansea on a season-long loan during the last knockings of the transfer window, and Liverpool confirmed on deadline day that he has completed a temporary move to the Championship club.
The Reds also revealed that the England Under-21 international has committed his future to the club for an unspecified period of time, believed to be five years until the summer of 2026.
Williams's only appearance in the 2021-22 season so far came in a Premier League 2 victory over Everton for the Under-23s, and his move to Swansea represents his second loan away from Liverpool following his temporary spell at Kidderminster Harriers.