A portable, retractable, and removable ultraviolet protective sunshade assembly that attaches to the headrest of a river or pool flotation tube by way of a backrest frame. The sunshade assembly provides a support frame that is telescopically associated with the backrest frame, enabling selective elevational adjustments of the support frame relative to the flotation tube. A shade frame is pivotably connected to the opposing end of the support frame so that a shade barrier is selectively rotatable between a plurality of operative positions over the user of the flotation tube as well as out of the way of the user.