El acuario - Isla de la Plata is a boat-access coral reef off Puerto Lopez inside Machalilla National Park, known for its color, relief, and seasonal megafauna. The profile is shallow to moderate rather than a big wall, so most dives stay close to the reef and watch for mantas, turtles, rays, and reef fish. Plan it through a licensed operator because access is managed and the island can feel more exposed when Pacific swell builds. June to October is the strongest window for conditions and wildlife.