Gadir is a tiny port on the north-east coast where three natural rock pools fed by thermal springs have been roughly squared off into bathing tanks at the edge of the sea. The water in the pools is hot — pleasantly so in the cooler ones, distinctly bracing in the hottest — and you can climb out and into the cold Mediterranean a few metres away.
It is a setting that has remained mercifully under-developed: a handful of dammusi, a single bar in summer, a couple of fishing boats moored against the lava harbour. Come early in the morning or at sunset to avoid the brief midday crowd, and combine the dip with a meal at one of the dammuso restaurants on the way back up to Tracino.