Introduction
Why does open water swimming attract you?
Swimming in a reservoir, a lake or a river changes your daily plan: sport, leisure and nature in the same place. In Spain there are hundreds of options, and here we gather lakes for swimming, river beaches and reservoirs with clear access and verifiable water quality.
Fresh water refreshes you in summer, but it demands respect. Currents, changes in depth, algae and boats are real risks, and it is worth taking them into account before entering.
Regulations change by autonomous community and by river basin. Verifying permits and reading signs is part of the plan, just like choosing spacious and supervised sites.
The selection discards points with explicit prohibition or with a high risk that cannot be controlled. As you approach the shore, the air smells of pine and damp earth. The goal is to choose well, avoid prohibited zones and enjoy with safety and common sense.
What you will find here
This guide helps you decide where to swim in open waters in Spain with clear regulations. It is organised into three parts: which criteria matter, where to go and how to prepare yourself.
First, the basic regulations and how to check them before heading out are explained. After that, there is a Top 12 with clear fact sheets for each place: access, best time, services and safety.
You also have how to plan your route with a base map, a quick checklist, recommended equipment and a frequently asked questions section with direct answers.
One piece of advice before anything else: enter slowly, metre by metre, to notice the change in water temperature.
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Regulations and permits: what you must know
In inland waters, swimming does not depend on a single administration: town halls, autonomous communities and Hydrographic Confederations share the competencies. Town halls set ordinances and services, the communities look after environmental health and recreational use, and the Hydrographic Confederations (Tajo, Ebro, Duero, Guadiana, Guadalquivir, Júcar, Segura, Miño-Sil) control reservoirs and riverbanks.
The Ministry of Health's Bathing Water Programme publishes the sanitary status of many areas every season. If the area is categorised, there are samplings and quality classifications.
The most common prohibitions affect drinking water abstractions, works or reservoir emptying, nesting or special protection zones, waters with "insufficient" quality and places without the minimum services required by some town halls. The signs rule: if there is a "Swimming prohibited" sign, respect it without exception.
In buoyed areas, the green flag indicates favourable conditions, the yellow flag calls for caution and the red flag temporarily prohibits swimming even if the site is usually suitable.
Before going, check the corresponding Hydrographic Confederation for works, reservoir emptying or closures, and consult the water quality reports published by the regional health authorities.
Once there, read the access signage, look at the buoys and respect the navigation zones.
Top 12 reservoirs, lakes and rivers to swim in safely
1. Sanabria Lake (Zamora): glacial shores and tranquil beaches
Sanabria Lake is the largest glacial lake in the Iberian Peninsula. It has wide shores, clear waters and a family atmosphere, within the Sanabria Lake Natural Park (Zamora, Castilla y León).
It is at an altitude of about 1000 metres and 15 km from Puebla de Sanabria. The swimming season runs from 15 June to 15 September and in summer the water is at 18–22 °C.
To get there from Benavente, take the A-52, exit at 79 in Puebla de Sanabria and follow the ZA-104 for 15 km. If you are coming from Ourense via the A-52, after the Puebla de Sanabria exit there are 2.5 km until the roundabout: take the third exit towards the ZA-104 and continue for another 15 km.
The ZA-104 leads to Ribadelago and to the beaches of Viquiella, Custa Llago and Los Enanos. There are signposted car parks and in summer there may be access control at popular beaches.
Swimming is permitted at the designated beaches: Los Enanos, El Folgoso, Grande o Viquiella and Chica o Custa Llago. Respect the buoys and the boats.
On windy days the surface ripples: stay near the shore if you do not feel safe far out.
2. Entrepeñas Reservoir (Guadalajara/Cuenca): wide coves and water sports
In the Alcarria, the Entrepeñas reservoir has coves with temperate waters and seasonal services. Pareja beach and the shores of Sacedón concentrate beach bars and water leisure activities.
The reservoir works well for medium-distance swimming, paddle surf, light sailing and outings with groups of friends. It is also a prominent area for sport fishing of pike, black bass, carp and tench. The best time is from June to September.
Swim within the marked zones and stay away from ramps and navigation channels. If there is a yellow flag due to wind or short waves, limit your distance and swim parallel to the shore. At Sacedón beach swimming is free, but parking has a cost in high season.
Wear water shoes, because many shores are stony, and check the water level before going: it varies depending on the year. Nearby you can walk along Alcarria paths, climb to viewpoints over the reservoir or go cycling on local tracks.
From Madrid, take the A-2 to Guadalajara and the N-320 to Sacedón, with local diversions to Pareja. Alcorcón de Sacedón beach is accessed via a dirt track from the town centre. There are buses from Madrid and Guadalajara capital (ALSA), with limited frequency.
3.Orellana Reservoir (Badajoz): inland beach with Blue Flag and family atmosphere
In Orellana la Vieja, there is a prepared sandy beach with an inland Blue Flag, right in the middle of the Orellana Reservoir (Badajoz, Extremadura). It has lifeguards during the season and rental of pedal boats and kayaks.
Facing the beach is the Isla de la Momia, an islet that serves as a reference for swimmers. The nearby buoys and the protected and supervised bathing areas make this spot a good choice for families, groups, and for starting out in open waters. Respect the buoy markings and the warnings from the beach staff.
The best time is from June to September, with 22–26 °C in summer. If a westerly wind blows, small waves form: orient your swimming parallel to the shore.
Nearby you can observe birds in the reservoir's SPA, walk routes through dehesas, and practice sailing and windsurfing with local operators. You can reach it via the EX-115 to Orellana la Vieja, with signage to the beach, and you can also go on foot from the village.
The car park is large and free next to the beach. In the blue zone, from 15 June to 15 September from 9:00 to 20:00, the rate is €0.20 per 90 minutes and the maximum parking time is 15 days.
4.La Jarosa Reservoir (Madrid): nearby nature and alternative bathing in San Juan
La Jarosa is the smallest reservoir in the Sierra de Guadarrama: 7.2 hm³ and 55 hectares. It is in Guadarrama, Comunidad de Madrid, and is a place for walking and spending the day, but swimming is not authorised.
On its shores, resinous pines, wild pines, and larch trees grow, as well as oaks, willows, and ash trees. The smell of resin from the pine forests accompanies you on the paths that border the shore. It is an intensive fishing area restocked with rainbow trout.
What to do in La Jarosa: hiking through the pine forest, viewpoints, and remains of the ancient road. It works well for picnics, family routes, and observing fauna. The best time for walking is from spring to autumn; the water is cold almost all year round.
You reach it via the A-6, Guadarrama exit, and access it via the M-614 regional road. In the reservoir, there are clear signs indicating the prohibition of swimming.
If you want to swim in open waters near Madrid, the official option is the San Juan reservoir, in San Martín de Valdeiglesias. It is the only reservoir in the Comunidad de Madrid where swimming and motorised water activities (sailing, water skiing, wakesurfing) are permitted. You reach it via the M-501, the road of the reservoirs.
In San Juan, the El Muro area, in Pelayos de la Presa, is officially authorised for swimming. It is advisable to use designated and buoyed beaches with services. From La Jarosa, you have to drive 1 h to San Juan and choose a supervised area.
5. Banyoles Lake (Girona): swimming tradition and urban services
Banyoles is lake and sport: swimming is permitted in three specific points because the entire surroundings are a protected natural area.
Swim within the areas marked with lanes and buoys and respect the supervision schedules. When the tramontana blows, the water becomes choppy, so it is advisable to swim close to the buoy line so as not to lose your reference. The lake works well for swimming training, for going with children, and for local sporting events.
Nearby, you can complete a full circuit around the lake via a completely flat route, rent a boat, or stroll through the historic centre of Banyoles. At the Club Natació Banyoles, they rent kayaks for 15 € per hour, and traditional rowing boats cost 10 € per hour for 4 people.
The lake is in the Pla de l'Estany, in Girona. You can reach it from Girona via the C-66 or by frequent interurban bus from the capital. There are perimeter car parks and designated areas near the Club Natació and the Parc de la Draga; there may be an entry fee in bathing areas during the season. In summer, the water is at 20–24 °C.
6. El Atazar Reservoir (Madrid): forest, immense views and restricted swimming
El Atazar reservoir is the largest in the Community of Madrid and the great sea of the Sierra Norte.
Strolling through viewpoints and silent coves is worth it: the wind carries the resinous scent of junipers and rockrose over the water. It is a good destination for hikers, for observing the landscape, and for authorised nautical activities.
Nearby you have the Senda del Genaro GR-300, the Pontón de la Oliva viewpoint, and the stone villages of the area. Spring and autumn are the best times to go on routes.
Before going, consult the regulations of the Community of Madrid and the on-site signage. Do not cross barriers or access forbidden coves.
Arrive via the A-1 to Torrelaguna and continue via the M-131 and the M-133 towards El Berrueco and the dam. There are car parks at viewpoints and recreational areas, without the usual fees.
7. Sella River (Asturias): natural pools and green adventure
The Sella flows through eastern Asturias between Cangas de Onís, Arriondas, and Ribadesella with tranquil stretches for a dip and pools of clear water. The current changes according to the flow, so the same spot can be a gentle pool or a demanding stretch.
In summer, canoe companies share the river with swimmers. Look for wide banks and choose the hours with the least traffic to swim with peace of mind.
Swim in calm banks and signalled pools, and stay away from rapids and canoe passages. After heavy rain, check the flow before entering, avoid weirs and undercut banks, and check submerged rocks before jumping. If the water is murky or high, cancel your swim and walk along the riverbank to a safer stretch.
The water is cold mountain water: enter slowly, do not swim alone, and limit your time inside. The best time is from July to September, and the river works well for experienced swimmers, for recreational canoeing, and for families who supervise closely.
Nearby you have the viewpoints of the Picos de Europa, the river path, and the chigres of the area. In Arriondas, the Mirador de la Concordia offers views of the Emilio Llamedo bridge and the Picos de Europa, and the river ends in the Cantabrian Sea forming the Ribadesella estuary.
Car parks are distributed in recreational areas and occupancy is high in high season, so arrive early.
8. Boltaña river beach / Ara River (Huesca): crystalline Pyrenees for a brief swim
It is a place for families who want to get wet and sunbathe among the mountains.
The swim is refreshing and short: enter progressively and use a thin wetsuit. If you feel numbness, get out of the water, warm up in the sun and go back in little by little.
The town hall marks the swimming area. Pay attention to the currents and the water temperature. With children, the plan works well: there is space for a picnic and clear pools for simple snorkelling.
Medieval Aínsa is 7 km away, about 7 minutes. Ordesa y Monte Perdido National Park is about 51 km away, approximately 1 h 27 min by car.
Arrive by car: there is signage to the river beach and nearby parking, and in summer there may be access control. Plan for a morning or an afternoon, preferably on hot days, and bring water shoes and a large towel.
9. Fuente de Piedra Lagoon (Málaga): bird watching and swimming alternatives in the region
The Fuente de Piedra Lagoon is a protected wetland in the Antequera region (Málaga, Andalusia) and a stop for flamingos.
To swim in fresh water in the area, you have to go to the Guadalhorce-Guadalteba reservoirs, in Ardales and El Chorro, with authorised beaches and supervision. Spring and autumn are the best times for birds; for swimming, summer in Ardales and El Chorro, with waters of 20–24 °C.
You arrive via the A-92, Fuente de Piedra exit, with the visitor centre signposted. If there is fauna concentrated on shallow banks, maintain distance and silence: here the protagonist is the flamingo.
Nearby you have the Caminito del Rey (with reservation), white villages, local cheese and oil. The Caminito del Rey opens from Tuesday to Sunday and closes on Mondays and on the 24, 25 and 31 of December and 1 of January. Access is prohibited to children under 8 years old; those under 18 must be accompanied by an adult and carry a DNI or passport. You must arrive 30 minutes before at the access point, located 25 minutes on foot from the El Kiosko restaurant (Conde de Guadalhorce reservoir); access is not permitted through non-authorised places, especially via the railway tracks.
10. Buendía Reservoir (Cuenca/Guadalajara): tranquil coves and turquoise water
Between Cuenca and Guadalajara, the Buendía Reservoir has wide shores, pine forests and water that turns turquoise when the sun is high. It is a versatile option: you can swim peacefully and then add a land route.
It works well for families, short trips, paddle boarding and kayaking. Access to the water is gradual, so avoid jumping from rocks and respect the municipal signage. If you notice waves from passing boats, adjust your route parallel to the coast and bring a visibility buoy.
Nearby you have the Ruta de las Caras de Buendía, viewpoints and walks through pine forests. To get there, take the A-2 to Guadalajara and follow the N-320 towards Auñón and Buendía with the local detours; the starting point is the Buendía dam, with a parking area. There is parking next to the coves and in summer there may be local regulation.
11.Ebro River (Authorised stretches): river beaches with local regulations
The Ebro flows with strength and demands respect: you can only swim in specific enabled stretches in Navarra, La Rioja, Aragón and Catalonia. The authorised stretches change depending on the year and the flow, so confirm with the town hall before going.
July and August are the best time, with water temperatures of 18–24 °C depending on the stretch and the year. The river suits experienced swimmers, families on supervised beaches and recreational kayaking.
Access points are urban or peri-urban depending on the municipality, with municipal car parks that sometimes have a maintenance fee during the season. Nearby there are greenways, meanders, viewpoints and riverside gastronomy.
Respect municipal decrees and signs. Do not swim after floods, outside the buoys or in navigation channels; if the level rises or the current accelerates, get out of the water and wait for better conditions.
12.Conde de Guadalhorce Reservoir (Málaga): inland beaches and emerald coves
The Conde de Guadalhorce reservoir, in the El Chorro environment (Ardales, Málaga), has emerald-coloured waters, inland beaches and pine shade. It is a place to swim with family or in a group.
The swimming season runs from June to September, with water temperatures of 20–25 °C. Families and groups find a comfortable plan here, with paddle surfing and short crossings in the early hours. At sunrise the water is calmer, good for a parallel round trip along the shore.
Nearby are the Caminito del Rey (with reservation), viewpoints and historic dams. The surrounding cliffs are a zone for climbing and wildlife. In the reservoir, barbel and carp live in large numbers and pike in small quantities, and birds such as choughs, pigeons, kingfishers, swifts, owls and griffon vultures stand out.
Do not swim in proximity to the dams and respect the limits of the swimming zones. Arrive via the A-357 with a detour to Ardales/El Chorro, or by car from Ardales via the MA-5403. There are signalled accesses to the inland beaches and car parks next to the swimming areas, with possible fees in high season.
Location map and how to plan your route
An interactive map brings together the bodies of water where swimming is permitted and lets you filter them to your liking. You can choose between reservoirs, lakes and rivers, narrow down by autonomous community and search for the services you need: lifeguard, toilets or beach bar.
The filters go even further. Adjust by estimated temperature and by type of swimming, whether with family, for training or for snorkelling. With the zoom, you can travel through the river basins and mark favourites to put together a circular or weekend route.
Before leaving, check the local regulations at the town hall and at the corresponding Hydrographic Confederation. Afterwards, check the water quality in the current regional health lists.
With the green light, define the logistics: parking, pedestrian access, shade and services. Book nearby rural accommodation to get up early and avoid the heat, and draw up a plan B in case there is wind, roadworks or full capacity.
A good route combines two or three places within a 60–90 minute driving radius. Spread out swims and walks during the coolest time slots.
Practical tips for choosing the right place
Choosing the right swimming spot saves you from scares and lets you swim more peacefully. Before getting into the water, spend a few minutes looking at the surroundings and checking four basic things.
Prioritise marked areas and, if you are going with children, places with a lifeguard and progressive entry into the water. Check the regulations and signs: ensure swimming is permitted and that the flags are operational. Also check the available services (lifeguard, toilets, showers, shade, and nearby food) and pay attention to the access points: type of ground, progressive entry, stairs, or ramps.
Before swimming, smell the water and observe: transparency, the absence of strange foams, and bottoms without rubbish are good signs. Upon arrival, look at the colour of the water and the bottom; it is better if the bottoms are visible at 1–2 m. Look for recent water quality samples and health warnings before going, and consult the weather and wind forecast: avoid swimming in case of a storm.
Once in the water, locate easy exits and landmarks on land, and identify buoys, lanes, and vessel zones. Define a route parallel to the shore of 10–15 min round trip. To avoid crowds, get up early on weekends and avoid peak hours and saturated coves.
Equipment and safety for swimming inland
Inland waters are governed by temperature, and visibility changes significantly from one point to another. Adapt your equipment and distance to your level and the environment before getting in.
Enter calmly: the first cold shock in your chest is the best alarm not to rush the entry. Carry a safety buoy with a flag or bright colour, which gives you visibility and support, and a brightly coloured cap. Goggles, clear or dark depending on the light. For your feet, flip-flops or water shoes if you enter via rocks or pebbles. If you swim coastal-parallel and there is coverage, keep your mobile phone in a waterproof bag.
Neoprene depends on the water temperature and your tolerance to the cold:
- Above 24 °C, swim without neoprene or with a thin shorty.
- Between 18 and 23 °C, a 2–3 mm neoprene, long or short sleeves depending on the cold.
- Between 15 and 18 °C, a full suit of 3–4 mm.
- Between 12 and 15 °C, 4–5 mm and a thermal cap.
- Below 12 °C, it is technical use and experience is required: consider not swimming.
Never swim alone: let someone know your plan and your return time. Swim parallel to the shore and avoid crossing vessel paths. If you get a cramp, float with the buoy, stretch gently, breathe, and return slowly. In the event of shivering and clumsiness, which are signs of hypothermia, get out of the water, dry yourself, bundle up, and get warm.
Frequently asked questions
Who decides if I can swim in a river, lake, or reservoir?
Three administrations share the decision. The town hall sets the ordinances and local services, the autonomous community monitors environmental health, and the Hydrographic Confederation manages the riverbed or the reservoir.
It is enough for one of them to prohibit swimming for you to be unable to get into the water, even if other sources recommend it. Before leaving, consult the regulations of those three administrations for the specific spot where you plan to swim.
Do I need permission to swim on my own?
In designated swimming areas, you can swim on your own without asking for permission. You just need to respect the local rules and the instructions from the surveillance services.
Things change if you organise a crossing, an event, or use boats. In those cases, you usually need to notify or ask for authorisation from the town hall and, depending on the case, from the corresponding Confederation. Check before fixing the date so you don't run out of time.
What temperatures can I expect?
In summer, inland water is usually between 20 and 26 °C in plain areas and between 14 and 20 °C in mountain areas. The difference between a valley reservoir and a plateau one is noticeable as soon as you enter.
In spring and autumn, the water temperature is usually between 12 and 20 °C. In winter, it is often below 10 °C, so consider whether a short swim is worth it for you.
Before jumping in, check the local temperature data and enter the water progressively. A short swim at the beginning helps you adapt without any scares.
What are the main risks?
Cold water, the bottom you cannot see, and boats are the three fronts that cause the most scares in a reservoir or a river. Knowing them helps you swim with a margin of safety.
Near dams, there are currents and suction: keep your distance from the structure and its surroundings. The depth can change suddenly, so do not dive headfirst without knowing the bottom. When entering, do so progressively to avoid the cold shock.
If the water is murky or has green foam, avoid swimming: there may be cyanobacteria during specific episodes. With low visibility and boats nearby, make yourself visible and swim near the shore. When entering and exiting, wear water shoes or step on firm ground to avoid slipping.
Reduce your exposure time and follow the signs and instructions of the environment.
How do I get information before going?
Before going, consult the municipal website, the Hydrographic Confederation of your basin, and the seasonal reports from the regional Health department (Bathing Water Programme). There you will see if swimming is permitted in that area and on which dates.
Upon arrival, read the signs and observe the buoys and flags to know if swimming is permitted and in which zone.
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Conclusion
Spain brings together fresh waters for all tastes: from family river beaches to quiet coves for training. Always choose designated areas, check the local regulations, and bring the appropriate equipment for swimming. With those three things, swimming is enjoyed more and the risk decreases.
A good option is to go through the Top 12, choose two nearby destinations, and set up an escape that combines swimming and hiking. If a place is prohibited or overcrowded, move to plan B and return another day.