Swimming at Cala Mariolu is generally very safe due to the cove's sheltered location and exceptional water clarity. The beach is protected by surrounding cliffs, which minimize currents and waves. The distinctive small white pebbles make for a comfortable seabed, though water shoes can be helpful. The water deepens gradually near the shore, suitable for most swimmers. The remarkable clarity allows you to easily see the bottom, adding to the sense of safety. However, the rounded pebbles can be slippery when wet, so take care when entering and exiting the water.

The optimal time to visit Cala Mariolu is during June or September when weather is excellent but crowds are lighter than peak August. For daily timing, arrive early morning when tour boats first dock, or later in the afternoon when day-trippers depart. The cove receives good sunlight throughout the day, with morning light particularly beautiful for photography. July and August offer guaranteed warm weather and calm seas but expect the beach to be crowded. Late spring and early autumn provide pleasant swimming temperatures with more breathing room to enjoy this spectacular setting.