Abstract: A rigid or inflatable stand up paddleboard (SUP) conversion kit to provide a stable recreational platform for fishing. diving, hunting, nature photography, birdwatching or other activity. A detachable frame positions a pair of pontoons rearward relative to the SUP to avoid interference with rowing. A rolling storage case stores activity accessories such as diving or fishing equipment. After securing the storage case to the SUP, the case serves as a storage seat. A rear canopy frame may be assembled onto the SUP in order to support a rear canopy to conceal the user; and a front canopy frame may assembled onto the SUP in order to provide additional concealment that may be used for a hunting dog. The various conversion kits are compact and self-contained, and can fit easily in the trunk of a car.