A device for exercising when partially submerged in water. The device includes a dumbbell shaped floatation member for providing buoyant resistance once submerged underwater. This dumbbell shaped member can accept extensions on either end thereof. A second dumbbell member and a second pair of extensions is provided. A third component of the buoyancy system is a buoyancy member that would threadably engage both dumbbell shaped members to provide for a barbell shaped device for submerging underwater and providing buoyant resistance for the user to work against. The pairs of extension may be threadably engaged either end of the barbell member.