The central defender was previously at Barnet and recently featured in their play-off campaign.
He spent three years at The Hive Stadium where he made a total of 84 appearances, netting six goals and has also played in the Football League with Peterborough where he enjoyed a two-year spell.
The 25 year-old, who stands at 6ft 6ins, was born in Portugal and moved to England as a youngster, joining the youth team of Dagenham & Redbridge in 2012.
Commenting on his arrival at the University of Bolton Stadium, Santos told bwfc.co.uk: “I am very happy to have signed for Bolton Wanderers and I am grateful for this opportunity. I cannot wait to get going.
“The club really sells itself and after having a brief chat with the gaffer, who told me about his plans, I just really wanted to be a part of it.”
Wanderers head coach Ian Evatt added: “We are delighted to have Ricardo Santos joining us.
“He is a player I have admired for a while. He is 6ft 6ins tall but is extremely quick and very good with the ball at his feet.
“Ricardo has all the attributes required to be an outstanding centre back for this football club.”
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