Flat Island lies off the northern coast, home to a historic lighthouse and former quarantine station.
Day trips combine its beaches with snorkelling stops around the surrounding reef.
Its relatively remote location keeps visitor numbers lower than southern islets.
Ruins from its quarantine past add a historical layer to the visit.
*Photo: Algonkins, Public domain, via Wikimedia Commons.*
Photo: Algonkins, Public domain, via Wikimedia Commons.