A suspension system for an amphibious vehicle is described, the suspension system being able to be locked in either a lowered or in a retracted position according to whether the vehicle is on land or in water, respectively, the suspension system comprising: a main suspension arm (14) pivoted to a vehicle hull at one end thereof (20), the arm having a rotatably mounted road wheel (12) thereon at an opposite end thereof; moving means (30) operably attached to said pivoted main suspension arm to enable said arm and said road wheel to be retracted relative to said hull; an upper suspension link (120) operably and pivotally connected to the road wheel end of said main suspension arm, said upper suspension link having a pivoted joint (60) intermediate its ends; said upper suspension link being pivoted on said hull at an axis (52) remote from said pivoted joint; said upper suspension link being operably engagable with suspension position locking means (122, 130, 132, 136, 138) in both lowered and retracted positions.