The 21-year-old has agreed a two-year deal with the Scottish Premiership club.
Fulton has been with Liverpool for 10 years and has had loan spells with Portsmouth and Chesterfield in the past two seasons.
Accies began the campaign with Gary Woods in goals for their League Cup win at East Kilbride.
Fulton will provide competition for Woods and Darren Jamieson, who was on the bench at the weekend.
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Hamilton Academical have signed Scotland Under-21 goalkeeper Ryan Fulton from Liverpool.