Cala Petrolo is generally safe for swimming and popular for snorkeling due to its rocky, clear waters. The small cove is protected from strong currents, though the seabed is rocky rather than sandy, so water shoes are recommended. The clarity of the water makes it excellent for observing marine life. Access involves steps or paths down to the cove, which may be challenging for some visitors. As a smaller, less monitored beach, swimmers should be confident and aware of their abilities. Check weather conditions before visiting, as the small cove can become choppy in wind.

To enjoy Cala Petrolo with fewer crowds, visit early morning or late afternoon during summer months, or plan your trip in May, June, or September. The small size of the cove means it fills quickly, especially in July and August when local and Italian tourists frequent the area. Weekdays are generally quieter than weekends. Early autumn offers pleasant water temperatures with reduced visitor numbers. The location beneath Castellammare's historic center makes it easily accessible, so timing your visit outside peak midday hours provides a more peaceful experience in this intimate, scenic cove.