Go for a stroll by the water's edge and breathe some fresh air at Houmt Souq Harbour. It's always nice watching the boats coming and going.
This place for ships to anchor is located in Houmt Souk. Once you've explored all you can at Houmt Souq Harbour, pay a visit to nearby El Ghriba Synagogue, Djerbahood, and Borj El K'bir Fort.