The coast around Antalya enjoys some of the warmest seawater in Turkey, courtesy of the eastern Mediterranean. But the sea keeps its own calendar: water warms and cools far more slowly than air, lagging the seasons by several weeks. That is why October water is warmer than May water even though the months feel similar on land — and why knowing the monthly curve helps you plan the most comfortable dive.
Sea temperature month by month
These are typical values for the Antalya coastline; individual years vary by a degree or so either way.
- January — around 17°C: the cool season; fresh but far from freezing.
- February — about 16–17°C: usually the coldest water of the year.
- March — around 17°C: the curve stays flat; the sea is slow to wake.
- April — 17–18°C: the first gentle rise begins.
- May — 20–21°C: warming accelerates noticeably.
- June — 23–25°C: genuinely pleasant water arrives.
- July — 26–28°C: peak-season warmth.
- August — 28–29°C: the warmest water of the year, almost bath-like.
- September — 27–28°C: the sea holds its stored summer heat.
- October — 24–25°C: warmer than May — autumn's open secret.
- November — 21–22°C: a mild, gradual decline.
- December — 18–19°C: easing down towards winter.
Why autumn beats spring in the water
Water has enormous thermal inertia: it stores the summer's heat and releases it slowly. The result is an asymmetric year — in October you swim in 24–25°C water under mild autumn skies, while in April, when the air can feel similar, the sea is still only around 18°C. If your priority is warm water rather than peak-season crowds, late September and October are quietly excellent months on this coast.
Does it get colder at diving depth?
At the depths we dive — a first dive at 5–8 metres and a second at 12–13 metres — the temperature usually stays close to the surface reading, though it can be a degree or two cooler, especially in high summer when the sun-warmed surface layer sits above slightly cooler water. You may feel a soft, cool transition as you descend; it is normal, brief and nothing like the dramatic thermoclines of deep lakes. Your instructor covers what to expect during the briefing.
Wetsuits are included — and they genuinely matter
Here is the counterintuitive part: even 28°C water cools your body far faster than 28°C air, because water conducts heat away from skin much more efficiently. Sitting still and breathing calmly for half an hour, you would eventually feel chilly even in August. That is why a wetsuit is part of the standard equipment package on every one of our trips, alongside the tank, regulator, mask and fins. The crew helps you find the right size on board, and the suit does double duty as sun and scrape protection.
So when should you book your dive?
From a pure comfort perspective, late May through October is the easiest window for first-timers: warm water, gentle conditions and no willpower required to climb in. High summer offers the warmest sea of all, while the shoulder months trade a degree or two for quieter boats. Availability varies through the year, so simply message us for current availability on your travel dates and we will confirm what is running.
Wherever you are staying, there is a departure point nearby: our full-day boat trips leave from Side, Kumköy, Kemer, Antalya and Alanya, each with two guided dives, all equipment, hotel transfer, fresh lunch on board and insurance for €43–€50. Browse the full list of trips, reserve free online and pay on the day — the Mediterranean will be exactly as warm as this guide promised.
