The sea off Marbella
The air here is easy to look up and the water is not. This is the sea: 23.9 °C in August at the peak, 15.2 °C in February at the floor, 5 months at or above 20 °C, and the official answers to the three questions people actually ask at the water's edge, which are whether it is clean, whether there are jellyfish and what the flag means.
Sea temperature from a 2023-2025 reanalysis at a grid point off Marbella; bathing, jellyfish and flag facts from the Junta. Read 4 September 2026.
Month by month
The sea runs about two months behind the air, which is the single most useful thing to know about swimming here. It is coldest in February, not in January, and warmest in August, not in July, so the last week of the season is warmer than the first week of the summer. On this reading the water sits at or above 20 °C from June to October. The daily extremes matter as much as the mean: the warmest single day in the record reaches 28.6 °C, and the same month can hold a day several degrees cooler.
Daily means over 2023-2025 at 36.458 N, 4.875 W, averaged per month. The exact query
Is it clean
Yes, and this is checkable rather than a matter of opinion. The Junta de Andalucía samples 12 separate bathing zones inside Marbella and publishes the results as a report every fortnight through the season, naming each zone, the inspection date, its annual classification and anything the inspectors noticed. On the most recent report, from 2 September 2026 on samples taken 24 August 2026, all twelve were fit for bathing with nothing recorded against them. Each zone carries the top annual classification except the two sampling points at Los Monteros, which are recorded as unclassified rather than as a problem.
- Marbella bathing zones officially sampled
- 12
- Sampling season
- 1 June to 30 September, a report each fortnight
- Most recent report
- 2 September 2026
- Result for Marbella
- All twelve fit for bathing, no observations recorded
Jellyfish
There are two official routes and they answer different questions. The Junta's fortnightly report records jellyfish per zone in the same observations column as algae and closures, which tells you what happened but not what is happening. For today, the answer is Infomedusa, run by a marine foundation with the provincial council: a daily forecast plus verified public sightings and the lifeguards' own flag, for 176 beaches on this coast. It is an app, with no public web map, which is why this page cannot show you a live figure. Four species turn up here regularly, and only one of them is a genuinely bad sting.
- Pelagia noctilucaHigh
- Rhizostoma luteumMedium
- Rhizostoma pulmoMedium
- Cotylorhiza tuberculataLow
What the flag means
The flag is not advisory. Andalusian law defines three colours and makes the red one a prohibition you can be reported for ignoring, and the lifeguard service is the body that raises, watches and changes it. A fourth flag for marine fauna is widely described and is not defined in the article that defines the other three, so it is not stated here as law.
Questions
How warm is the sea in Marbella?
It peaks at about 23.9 °C in August and bottoms out around 15.2 °C in February. The full month-by-month table is above. Those are means of daily values over 2023-2025, from a reanalysis at a grid point off the coast rather than from a buoy.
When can you swim in Marbella?
If your threshold is 20 °C, the water is there from June to October on this reading, which is 5 months. Plenty of people swim well outside that; the threshold is this page's, not the sea's.
Are there jellyfish in Marbella?
Sometimes, and there is a daily source for it: Infomedusa, an app run by a marine foundation with the provincial council, covering 176 beaches on the Málaga coast with a forecast, verified sightings and the lifeguards' flag. The Junta's fortnightly bathing report also records them per zone, after the fact.
Is the water in Marbella clean enough to swim in?
On the most recent official report, 2 September 2026, all 12 sampled Marbella bathing zones were fit for bathing with no observations recorded. The Junta publishes that report every fortnight through the season, so it can be checked rather than taken on trust.
What does a yellow flag mean on a Marbella beach?
Bathing is allowed but under stated limitations, because of the sea state, marine animals, floating material or anything else the lifeguards judge a risk. Red means bathing is prohibited outright, and swimming under a red flag is an offence, not a suggestion.
The monthly temperatures are the mean of daily sea-surface values from a marine reanalysis at a grid point off Marbella, over the three complete years 2023-2025, and they are a model output rather than a thermometer in the water. That is a deliberate second choice: Puertos del Estado publishes its Málaga buoy as a chart with no downloadable climatology and no monthly table, and the state meteorological agency's data interface needs a key it does not issue on request. The number of days behind each month's average is printed beside it so a thin month is visible. Everything else on this page, the bathing zones, the jellyfish route and the flag meanings, comes from the Junta de Andalucía and from the decree that defines the flags, and none of it is summarised beyond what those sources say.
Air temperature, rain and sunshine are a different measurement and live on the weather pages, month by month, from the state agency's own thirty-year normals. Where to actually swim is the beach guide.