September in Spain? You’ve basically hit the sweet spot for swimming. The sea is at its warmest after months of summer sun, the tourist crowds have thinned out, and the weather is still gorgeous without being oppressively hot. Honestly, if you want the best swimming conditions without the July-August chaos, September is your month.
Here’s why September rocks: the Mediterranean has been heating up all summer, so water temps are actually warmer than they were in June or even early July. You get pleasant 77°F (25°C) sea temps, fewer people competing for beach space, and that perfect late-summer vibe when everything feels a bit more relaxed. Let me break down exactly where you should swim in Spain this September.
Is the Sea Actually Warm in Spain in September?
Short answer: Yes, very warm. Spain’s sea temperatures in September average around 77°F (25.3°C), which is considered “pleasant swimming” across most coastal areas.
Why it’s often warmer than June/July: The Mediterranean is an enclosed sea that absorbs heat all summer. By September, it’s reached peak warmth even though air temperatures are cooling slightly. Think of it like a bathtub that’s been warming up for three months – it doesn’t cool down immediately when you turn off the tap.
Regional breakdown:
- Alicante (Costa Blanca): 77°F (25°C) average
- Barcelona: 76°F (24°C) average
- Málaga (Costa del Sol): 72°F (22.3°C) average
- Canary Islands: 73°F (22.7-23°C) average
- Northern Atlantic coast (Bilbao): 70°F (21°C) – cooler but still swimmable
Weather conditions are ideal: about 8 hours of sunshine daily, minimal rainfall, and air temperatures around 79°F (26°C) on the Costa del Sol. September gives you warm water without the extreme heat.
Warmest Beaches in Mainland Spain (Mediterranean Coast)
Costa del Sol (Málaga & Marbella)
The “Sun Coast” delivers in September with sea temps averaging 72°F (22.3°C). Water can reach up to 81°F (27°C) early in the month and stays comfortable even into late September, ranging from 70-73°F.
Air temperatures average 79°F (26°C), making the water feel refreshing without being cold. The Costa del Sol enjoys about 8 hours of sunlight daily. Popular beaches like Málaga city beaches, Marbella’s upscale stretches, and Nerja’s dramatic coves all offer excellent swimming conditions.
The water is calm and ideal for long swims, especially in the morning before any afternoon breezes pick up. This is perfect timing – warm enough for extended swimming, cool enough that you don’t overheat on the beach.
Costa Blanca (Alicante & Benidorm)
This is where the warmest Mediterranean water is found. Alicante averages 77°F (25°C) in September, with water reaching up to 81°F (26°C). The sea rarely drops below 74°F.
Air temperatures average 77°F (25°C) with minimal rainfall – only about 2 days of precipitation for the entire month. Cloud cover is just 18%, so expect sunshine and gorgeous beach days.
Costa Blanca beaches like Playa de San Juan in Alicante, Levante Beach in Benidorm, and Granadella in Jávea are Blue Flag certified with excellent facilities. The combination of warm, calm water and infrastructure makes this ideal for families and anyone who wants serious beach time.
Costa Cálida (Murcia) – Mar Menor Lagoon
Here’s the secret weapon: the Mar Menor lagoon is one of Spain’s warmest swimming spots in September. The Region of Murcia sees water temps around 77-79°F (25-25.4°C). The warmest recorded September temperature was 79°F (25.4°C) in Los Alcázares.
The Mar Menor is a massive shallow lagoon – only about 23 feet deep max – so it heats up like a natural warm pool. The water is incredibly calm, making it perfect for families with young kids, elderly swimmers, and anyone who wants relaxed swimming without waves.
The surrounding Mediterranean coast in Murcia also maintains excellent temperatures around 77°F (25°C). This entire region is seriously underrated for September swimming.
Catalonia (Barcelona & Costa Brava)
Barcelona sea temperatures average 76°F (24°C) in September, ranging from 71-81°F. Air temperatures average 76°F with about 5 rainy days in the month.
Barcelona’s city beaches (Barceloneta, Bogatell, Mar Bella) offer convenient urban swimming with full facilities, lifeguards, and easy metro access. For clearer water, head north to the Costa Brava – coves near Begur, Tossa de Mar, and Cadaqués have stunning clarity and warm September temps.
Best swimming times: Early morning (8-10 AM) or late afternoon (5-7 PM) when beaches are less crowded, and the light is beautiful.
Balearic Islands – Warm Water & Clear Seas
Mallorca
September in Mallorca offers sheltered bays and turquoise water that’s still beautifully warm. Water temps stay around 76-77°F (24-25°C) well into late September.
Best beaches for swimming:
- Cala Mondragó – protected natural park with calm, clear water
- Playa de Muro – long shallow beach perfect for families
- Cala d’Or – sheltered coves on the east coast
- Es Trenc – stunning white sand and crystal water
The south and east coasts are typically calmer than the north in September. Water visibility is excellent for snorkeling.
Menorca
Menorca’s legendary calas (coves) shine in September. The water is calm, shallow in many spots, and gorgeously clear. Temps match Mallorca at 76-77°F (24-25°C).
Cala Macarella, Cala Turqueta, and Son Bou are all stunning for relaxed swimming. September means fewer boats anchored in the coves, so you get that pristine water experience.
Ibiza & Formentera
Crystal-clear water and warm evenings make these islands magical in September. Water temps stay around 77°F (25°C). Playa de Ses Illetes in Formentera is consistently one of Spain’s warmest swimming spots.
Sunset swims are absolutely incredible – the water is still warm, the beaches empty out, and the light is golden. Beach clubs stay open, but are way less crowded than in August.
Canary Islands – Warmest Water Year-Round
Tenerife
The Canaries maintain reliable swimming weather year-round. September sees water temps around 73-74°F (23°C). Air temperatures average 81°F (27°C).
The south coast (Playa de las Américas, Los Cristianos, Costa Adeje) offers the warmest, most sheltered beaches. The north coast is cooler and can have rougher conditions.
Gran Canaria
Protected beaches and warm ocean currents keep Gran Canaria comfortable. September water averages 73-74°F (23-23.5°C), ranging from 70-79°F throughout the month.
Playa de las Canteras in Las Palmas is excellent – protected by a natural reef, it creates calm swimming conditions. Maspalomas in the south offers endless dunes and warm water.
Climate details: 8 hours of sunshine daily, minimal rain (2 days/month), low humidity around 69%. Perfect beach conditions.
Lanzarote & Fuerteventura
Slightly cooler water than the other islands, but still very swimmable at 71-73°F (22-23°C). The volcanic landscape is stunning.
Best sheltered swimming spots: Playa Blanca in Lanzarote, Corralejo in Fuerteventura. These areas avoid the worst of the wind and offer calmer conditions.
Where It’s NOT Ideal for Swimming in September
Northern Spain (Atlantic Coast)
The Basque Country, Cantabria, Asturias, and Galicia have cooler Atlantic waters. Bilbao averages only 70°F (21°C) in September, which is classified as “cool swimming”.
The water is swimmable if you’re hardy, and locals definitely go in, but it’s noticeably cooler than the Mediterranean. The upside? Fewer crowds, dramatic coastlines, and excellent surfing conditions – just not ideal for leisurely long swims.
Strong waves and rougher conditions make these beaches better suited for surfing than relaxed swimming.
Tips for Swimming in Spain in September
Best Time of Day to Swim
Early morning (7-9 AM): Calmest water, empty beaches, cooler air temps. Perfect for serious swimming.
Late afternoon (5-7 PM): Water is warmest after absorbing the sun all day, beaches are less crowded, beautiful golden light. Ideal for leisurely swims and sunset watching.
Jellyfish Awareness
Important: September is actually peak jellyfish season in Spain, especially in the Balearic Islands, Costa Brava, and Costa del Sol. The most common are the Mauve Stinger (Pelagia noctiluca), which can sting, and the harmless Barrel Jellyfish.
In Mallorca, September brings Cotylorhiza tuberculata – gorgeous and totally harmless jellyfish that look like fried eggs. They’re actually beautiful and won’t hurt you.
What to do:
- Check for purple flags at beaches (indicating jellyfish presence)
- Ask lifeguards about current conditions
- If stung, rinse with saltwater or vinegar – NEVER fresh water
- Seek medical help if the reaction seems severe
Don’t let this scare you off – jellyfish are common but not everywhere all the time. Just be aware and check the beach flags.
Sun Protection
UV is still strong in September. SPF 50+ sunscreen, reapply every 2 hours, UV protection shirts for extended swimming, hats, and sunglasses are essential.
Beach Flag Systems
Spain uses the standard color system:
- Green: Safe to swim
- Yellow: Caution, swim carefully
- Red: No swimming allowed
- Purple: Dangerous marine life (usually jellyfish)
Always check flags before entering water.
Sea Temperature Apps
Download apps like Windy.com or Seatemperature.org to check daily water temps and conditions before heading to the beach.
Packing List for September Beach Trips
- Multiple swimsuits (so one dries while wearing another)
- Quick-dry microfiber towel (easier to pack and dries fast)
- Light cover-ups (September sun is still strong, but evenings cool slightly)
- Water shoes for rocky Mediterranean coves and volcanic Canary beaches
- Snorkeling gear (water clarity is excellent in September; bring your own for hygiene)
- Reef-safe sunscreen (protects the marine environment)
- Light jacket for evening beach walks
FAQs
Can you swim in Spain in late September?
Absolutely. Water temperatures remain warm throughout the month. The Mediterranean averages 72-77°F (22-25°C) even into late September. The Canaries maintain 73°F (23°C) year-round. Late September actually has fewer crowds while keeping great swimming conditions.
Which part of Spain has the warmest sea?
In September, Costa Blanca (Alicante) and the Mar Menor lagoon (Murcia) have the warmest Mediterranean water at 77-79°F (25-25.4°C). For year-round warmth, the Canary Islands maintain a consistent 73-74°F (23°C). Formentera consistently ranks among the warmest for open ocean swimming.
Is Spain crowded in September?
Much less than July-August. European school holidays end in late August, so September sees significantly fewer tourists. Beaches, hotels, and attractions are more relaxed. Early September (first two weeks) is slightly busier than late September. It’s the shoulder season sweet spot.
Are lifeguards still on duty?
At major beaches, yes, though hours may be reduced compared to peak summer. Blue Flag beaches maintain lifeguard coverage through September. Always check local beach schedules and swim in supervised areas when possible.
Best Places to Swim in Spain in September
Quick ranking warmest to coolest:
Mar Menor lagoon (Murcia) – 77-79°F, incredibly calm
Costa Blanca (Alicante) – 77°F, warm and developed beaches
Balearic Islands – 76-77°F, crystal-clear water
Canary Islands – 73-74°F, year-round reliability
Costa del Sol (Málaga) – 72°F, classic Mediterranean
Barcelona/Costa Brava – 76°F, urban + natural coves
Northern Atlantic coast – 70°F, cooler but swimmable
Who should choose what:
- Families: Mar Menor or Costa Blanca for warmest, calmest water
- Couples: Balearic Islands for beauty and variety
- Snorkelers: Costa Brava coves or Menorca for visibility
- Year-round swimmers: Canary Islands for guaranteed conditions
- Culture + beach combo: Barcelona or Málaga
Final advice: Book accommodation early for the first two weeks of September – it’s still relatively popular. Late September offers the best deals and fewer crowds while keeping the warm water. Don’t skip the Mar Menor if you’re in the region – it’s seriously underrated and ridiculously warm. Watch for jellyfish, but don’t stress too much – they’re common but manageable.
September is genuinely one of the best months to swim in Spain. The water is warmer than summer started, crowds have disappeared, and you get that perfect balance of great weather without the intensity of peak season. Whether you’re floating in the Mar Menor, snorkeling in Menorca’s coves, or catching sunset swims in Ibiza, Spain’s September swimming is unbeatable.
