Mar Menor water temperature, month by month
The Mar Menor is a shallow lagoon, so it warms up much faster than the open sea. In August the water reaches ~29 to 30 °C, September still gives you ~26 °C, and even in October ~22 °C is perfectly normal. The comfortable swimming season here runs from mid May to mid October, longer than almost anywhere on the Spanish coast.
Why the Mar Menor gets so warm
The Mar Menor is Europe's largest saltwater lagoon, yet nowhere deeper than about seven metres. That thin layer of water catches the sun like a pan on a stove: in spring the temperature here rises weeks earlier than in the Mediterranean on the other side of the sand strip.
The same works in reverse in autumn: the lagoon holds its summer warmth for a long time, but in winter it cools further than the open sea. That is why you swim comfortably here in June while the sea is still fresh, and why February is for the brave.
When you can swim
From mid May the water passes 20 °C and the real season begins. June, July and August are bathwater, peaking near 30 °C in late August. September is our own favourite: the water is still ~26 °C, the beaches belong to the locals again and half the parasols stand empty.
October can be surprisingly good, with ~22 to 23 °C early in the month. From November to April the water is fresh, between ~13 and ~18 °C. People still swim then, but mostly the village's hardened morning swimmers.
Mar Menor or Mediterranean?
San Pedro del Pinatar has two coasts, and that is exactly the charm. In summer the Mar Menor is two to three degrees warmer than the Mediterranean, calm and without waves. The sea beaches on the far side of the salt lakes, such as La Llana, have fresher water, a breeze and small waves.
Our advice to guests: mornings and children at the lagoon, afternoon heat at the sea side. From our homes you can walk to both.
With children
Warm plus shallow makes the Mar Menor ideal for small children: in many spots you can stand fifty metres from the shore with water at your waist, and there are no waves. Children learn to swim here without blue lips.
Do stay close: shallow is not a babysitter. And keep applying sunscreen, because in shallow water the sun reflects from every direction.
Frequently asked questions
How warm is the Mar Menor in summer?
In July and August ~28 to 30 °C. The lagoon is shallow and heats up strongly; it feels more like bathwater than sea.
Can you still swim in the Mar Menor in October?
Yes. Early October the water is usually still ~22 to 23 °C. It only really drops in November.
Is the Mar Menor warmer than the Mediterranean?
In summer yes, usually two to three degrees. In winter it is the other way round: the shallow lagoon cools further than the open sea.
When does the swimming season start?
Around mid May the water passes 20 °C. The season runs until mid October, longer than in most of Spain.
Why is the Mar Menor so shallow and warm?
It is Europe's largest saltwater lagoon, nowhere deeper than about seven metres and almost closed off from the open sea by the La Manga strip. That thin layer of water heats up fast.
Are there waves on the Mar Menor?
Hardly any. For waves and fresher water walk to the sea beaches on the other side of the salt lakes, such as La Llana.
Walking distance from Spain's warmest water
Casa Flamingo is ~200 m from the lagoon beach, Casa Feliz ~500 m. Check the calendar to see if your swimming month is still free.
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Details checked on 2026-07-26