How warm is the sea around Mallorca in September compared to other times of the year?

If you're planning to swim or snorkel around Ses Illetes or Cala Mondragó in September, you'll find the sea at one of its most inviting temperatures. After soaking up the Mediterranean sun all summer, the waters typically warm to the mid-70s Fahrenheit (around 24°C), making beaches like Es Trenc and Formentor particularly pleasant for bathing. This late summer warmth lingers longer here than on the mainland, offering ideal conditions for water sports without the intense heat of July or August.

Earlier in the year, from spring through early summer, the sea can still feel quite fresh—especially on the north coast near Pollença or around the Serra de Tramuntana, where winds sometimes cool the water. By contrast, October and November gradually usher in cooler temperatures as the island moves towards autumn, and swimming becomes less comfortable despite the still mild air. If you prefer quieter beaches after the high season, September strikes a sweet spot with warm seas and thinner crowds, particularly along the Ma-19 road coastline or at secluded coves near Deia.

This balance makes September a favorite time for locals and visitors alike to enjoy classic island waters with a comfortable temperature and the kind of clarity that suits snorkelling around Caló Des Moro or exploring marine life off Cala Llombards. Whether you’re sipping Palo in a beachside chiringuito or hiking above the Soller valley after a swim, the sea temperature and peaceful atmosphere combine to create a subtly perfect end-of-summer experience.