A floating oil storage system and associated methods for storing oil are disclosed. In some embodiments, the floating oil storage system includes a storage cell, a floating member disposed within the storage cell, whereby the storage cell is divided into a first compartment and a second compartment disposed below the first compartment, a pump operable to deliver oil under pressure into the first compartment, whereby the first compartment expands and the second compartment contracts expelling seawater from the second compartment, and a suction tank operable to receive oil expelled from the first compartment under hydrostatic pressure of seawater in the second compartment, whereby the first compartment contracts and the second compartment expands receiving seawater.