The restaurant (a beach ranchón) is located on the beach area of Hotel Sol Cayo Guillermo, however it is not part of the resort facilities per se, so you might want to book your lunch or dinner in the morning hours.
Its menu is quite varied and of fine quality, according to the views expressed by clients in prestigious opinion forums such as Tripadvisor.com, where they also emphasize the generous size of its servings.
A helpful tip: If you’re visiting the restaurant at night and coming from the nearby Hotel Sol Cayo Guillermo, don’t forget to bring a flashlight, for this path is not properly lit.