Salt, the island's oldest export.

A lagoon the sea still fills

Ses Salines occupies the flat southern tip of Ibiza, where the land narrows towards the sea and the water has nowhere to drain. Shallow ponds run beside low dunes and pine, fed by the sea through a channel and dried by sun and wind. The natural park was declared in 2001 and covers the south of the island, the sea between Ibiza and Formentera and a strip of Formentera's north shore.

It is also a Ramsar wetland, a designation given to wetlands of international importance, and salt is still harvested here. That combination is unusual: a working industrial landscape that is also a protected natural site, with birds, plants and shallow water sharing space with the pans. Visitors walk along the edges rather than through the middle, and the scale of the place takes a while to register.

The salt pans are not a museum. Vehicles use the road that crosses the wetland, the airport is close, and the beaches along the dunes are busy in summer. What keeps the place working is the balance between those uses and the protection of the water. The Consell de Eivissa and the natural park office manage that balance, and the rules that follow from it are worth knowing before you arrive.

Worked since antiquity

Salt has been taken from these flats for a very long time. The Phoenician settlement at Sa Caleta and the necropolis at Puig des Molins show how early the island was tied into Mediterranean trade, and salt was one of the things that ships could carry away. In the medieval period the island passed to the kings of Aragon, and salt remained one of the goods that left the port. The pans have never entirely stopped working.

What the trade left behind is easier to see than the trade itself. The old town of Eivissa grew above the port that shipped the salt, and the walls of Dalt Vila, built in the 16th century, protected a town whose wealth came partly from the pans to the south. UNESCO recognised the island in 1999 under the title Ibiza, Biodiversity and Culture, joining the living landscape to the built one.

Salt has been taken from these flats for a very long time, and the pans have never entirely stopped working.

How a salt pan works

Sea water enters the ponds through a channel and then moves slowly from one shallow basin to the next. Each step raises the salinity a little as the sun and the wind take water away. By the last ponds the water is dense enough for salt to form, and the crystals gather on the bottom or float as a thin crust on the surface. Wind matters as much as heat here.

The harvest is a matter of timing and weather, and it changes from year to year. Workers draw the salt into low pyramids or ridges to drain before it is carried away, and the white shapes you see from the road are the result. The pans are shallow on purpose: a depth of water that can be warmed quickly and moved easily is what makes the whole system work.

• The intakeSea water is let into the first pond through a channel, often with a gate to control the flow.
• The sun and windShallow water warms fast and the wind keeps it moving, so the salinity rises.
• The crystalsIn the final ponds salt forms and settles, ready to be drawn out.
• The harvestSalt is piled to drain, then carried away; the timing depends on the weather.

The salt road and the towers

Salt leaves a mark on the coast. Watchtowers were built along the shoreline over several centuries to warn of raids, and the tower above Es Savinar, looking across to Es Vedrà, is the best known of them. From the salt pans boats could move north to the port of Eivissa or south across the water, and the coast between was watched. Walking any part of that coast today gives a sense of how exposed the island was.

The towers are usually described as defence, but they were also an early warning system for trade. A sail on the horizon could mean a merchant ship collecting salt or a corsair coming to take it. The chain of towers could pass a signal along the coast in a short time. Several are reachable on foot, and the walks that link them follow the same cliff paths that once carried lookouts.

If you walk the coast, take the same care as anywhere on the island: water, a hat, shoes with grip, and a plan that does not depend on a phone signal. The cliffs are soft in places and the paths run close to the edge. None of this is dramatic. It is simply how a small island with a long memory of wind and weather expects visitors to behave.

Dunes, pines and birds

Behind the ponds runs a belt of dunes fixed by juniper and pine, and behind that the flat land where the airport sits. The dunes are part of the natural park and are more fragile than they look: the plants that hold them in place take years to establish and a few footsteps can open a gap that the wind widens. Boardwalks and marked paths exist so that feet stay off the most sensitive ground.

The shallow water and the shelter of the pines make the area good for birds, particularly on migration in spring and autumn. Flamingos and waders sometimes appear on the ponds in the quieter months, and the dunes and saltmarsh hold species that are hard to find elsewhere on the island. Early morning is the best time, before the wind picks up and before the day's traffic on the road behind.

• Stay on the pathsThe dunes are held together by plants, and a single shortcut can start a blowout.
• Keep off the crustThe surface looks solid but is thin; walking on it damages the structure of the pan.
• Bring binocularsThe ponds are large and the birds are often far off, so a lens makes a difference.
• Dogs on a leadGround-nesting birds are easily disturbed, so keep dogs close or leave them at home.

The meadow that makes the salt

The clear, clean water that the salt pans depend on does not happen by accident. Posidonia oceanica, a flowering seagrass found only in the Mediterranean, meadows the sea floor between Ibiza and Formentera, filtering the water and holding the sand in place. The UNESCO listing of 1999 took in those meadows, and the natural park protects them along with the land. The salt, the beaches and the clarity of the water are one system.

Anchoring over the meadows is regulated by a Balearic decree, and mooring buoys are installed in some bays in summer. If you arrive by boat, use a buoy where one exists or anchor over sand, and check the current rules with the natural park office or the Consell de Eivissa. On land the same logic applies: the dunes, the salt crust and the shallow ponds all repay a little distance.

Getting there and when to go

The salt pans lie a short drive from Eivissa and from the airport, and the road south from the city passes the edge of the ponds. Buses run along that road, with more of them in summer; check the island bus operator for current times. Cycling is possible, though the road carries traffic and the middle of the day is hot and exposed.

Spring and autumn are the most comfortable months, with fewer people and better light. In high summer the car parks near the beaches fill early and the heat is serious by mid-morning. Access points, opening arrangements for any visitor facilities and the rules on vehicles all change; check with the natural park office or the Consell de Eivissa before setting out, and carry water.

Salt at the table

Salt from these pans is a food product as well as a landscape. Coarse salt is used for the oven and the grill, and the fine crust that forms on the surface is skimmed and sold as a finishing salt. The flavour comes from the same clean water and slow evaporation that make the place worth visiting. It is the plainest possible export and the one that has lasted longest.

Cooks on the island treat it as a local ingredient rather than a souvenir, and it turns up in simple things: grilled fish, vegetables, bread with tomato. Buying it from a shop in Eivissa or Santa Eulària keeps the money on the island, and the salt keeps for years in a dry cupboard. There is no need to buy more than you will use.

The pans also explain something about the island's economy. Long before music and night flights, Ibiza exported a mineral that every kitchen in Europe needed, and the harbour at Eivissa existed partly to move it. That older trade is still visible in the flat southern landscape and in the names on the map. It is a quieter story than the ones told about the island, and a longer one.

• Coarse saltFor the oven, the grill and preserving; the grain is large and slow to dissolve.
• Finishing saltThe thin crust skimmed from the surface is used raw, at the end of cooking.
• Keep it drySalt takes up moisture from the air, so a sealed jar in a cupboard is best.
• Buy localShops in Eivissa and Santa Eulària sell island salt; ask which pans it came from.