A device for mounting an umbrella to a seat； the device includes a seat-sleeve, an umbrella-sleeve, a first-cantilever, and a second-cantilever. The seat-sleeve has a tubular sidewall and a cylindrical cavity within the sidewall. The sidewall of the seat-sleeve is constructed to allow a support of a seat, particularly a boat-seat, to pass through the seat-sleeve, in such a way that the support can slide and rotate freely within the seat-sleeve. Likewise, the umbrella-sleeve also has a tubular sidewall and a cylindrical cavity within the sidewall. The sidewall of the umbrella-sleeve is constructed to allow the shaft of an umbrella to pass through it in such a way that the shaft can slide and rotate freely within the umbrella-sleeve. The first-cantilever and the second-cantilever each are attached to both the seat-sleeve and the umbrella-sleeve, enabling the device to mount the umbrella to the boat-seat.
