​​Solar eclipse 2026: What recreational sailors need to know

Motorboat owners in the Balearic Islands will face an unusual challenge on 12 August 2026: the Mediterranean off the coast of Mallorca will be more crowded that evening than it has ever been before. According to estimates by the authorities and industry associations, more than 10,000 boats will be out on the water at the same time to watch the total solar eclipse. Anyone wishing to take part in their own boat or a charter vessel will need to secure a good position, have sufficient fuel to last whilst waiting to reach their position, and be familiar with the applicable safety regulations.

Mallorca and Ibiza: the best 90 seconds of the summer

The Balearic Islands are at the heart of the event. Mallorca, Menorca, Ibiza and Formentera lie entirely within the path of totality. In Palma de Mallorca, totality begins at around 8.31 pm CEST and lasts for around 90 seconds. Ibiza follows shortly afterwards: in Sant Antoni, it begins at around 8.33 pm and lasts for around 80 seconds.

The event in the Balearic Islands promises to be something very special. Because the sun is so low in the sky, the moon’s corona will glow directly above the water’s surface. The reflection on the water’s surface will enhance the visual effect. Anyone at anchor in open water will, ideally, be surrounded by water on three sides and have a completely unobstructed view to the west-north-west.

On the mainland, however, road closures and large crowds are expected in the most popular areas of Mallorca.

​Minimum distance and navigation safety: What the authorities require

The Balearic Government has drawn up a specific safety plan for this event: the ECLIPBAL 26 programme. Under this plan, a recommended minimum distance of three nautical miles from the coast applies to pleasure craft; for larger vessels, a distance of five nautical miles is under discussion. Anyone setting sail from a marina or harbour should monitor VHF channel 16 at all times and maintain a safe distance from other vessels. With tens of thousands of boats in a confined space, defensive navigation is essential. It is advisable to set out early to ensure you are in position in good time before the partial phase begins at around 19:28.

Times and cloud cover by location

All times are in CEST.

The North Sea, the Baltic Sea, the Netherlands: 84 to 90 per cent – and still well worth a visit

Along the entire German North Sea and Baltic Sea coast, as well as in the Netherlands, the coverage ranges from 84 to just over 90 per cent. That may sound unspectacular, but it’s still worth taking a look. At 84 per cent cloud cover, the sun becomes a narrow crescent; the quality of the light changes noticeably, and colours and shadows take on an unfamiliar quality. Anyone who has experienced this once on a calm sea will never forget it.

Sailors on the Kiel Fjord, off Rügen, in the Wadden Sea or along the Dutch coast benefit from the same basic principle as everyone else: the deck offers an unobstructed view to the west-north-west, with no houses, no trees and no mountains. At the time of maximum, the sun is already low in the sky, just two to three degrees above the horizon; anyone lying off a wooded shore or anchored in a bay will see correspondingly little.

The darkness literally accompanies the sunset. The crescent sinks below the waterline, tinged with red – a sight that is rare even without totality. Along the German coast, depending on the location, the sun sets between 8.50 pm and 9.05 pm; in some regions, the spectacle therefore ends slightly earlier than would be astronomically possible.

Inland lakes are only worth visiting on one condition: the western shore must be unobstructed. On Lake Constance, Lake Müritz or Lake Chiemsee, the view to the west may be clear enough to allow you to follow the event properly from on board. Anyone moored in a wooded or built-up bay should have moved to a more favourable position by 7.00 pm at the latest.

Spanish Mediterranean coast: Total eclipse right on board

Anyone currently staying on the Costa Daurada or the Costa del Azahar is right in the path of totality. Tarragona and its coastline, as well as the region between Castellón de la Plana and Valencia, are among the areas where the Moon will completely obscure the Sun – right over the sea.

According to the Spanish National Institute of Geography (IGN), the path of totality runs from west to east through Oviedo, Bilbao, Zaragoza, Tarragona and Valencia, ending in Palma de Mallorca.

An important practical tip for boats off the east coast of Spain: as the sun is only two to five degrees above the horizon at the time of totality, from a boat anchored off the coast, the land will be to the west or north-west. In other words, exactly in the direction from which the eclipse is approaching. Anyone moored too close to the coast or anchored in front of hills risks having their view obscured during the final few metres above the horizon. A distance of at least two to three nautical miles from higher coastal terrain is recommended for an unobstructed view of the low-lying sun.

On the French Mediterranean coast, On the Côte d’Azur, in Marseille and Nice, the eclipse will remain partial; however, according to observation websites, it will be very pronounced, with around 95 to 96 per cent of the Sun covered. Even from on board a ship off the coast of Nice or Marseille, the crescent-shaped sun can be observed impressively above the western horizon. However, it will not become completely dark on the French Riviera.

Never underestimate the importance of eye protection on the water

The following applies without exception to all phases before and after totality: ISO-certified solar eclipse glasses in accordance with standard 12312-2 must be worn at all times. Ordinary sunglasses do not provide adequate protection. On the water, the reflection off the water’s surface significantly increases the glare.

It is only safe to look directly at the sun without protection during the few seconds of actual totality. As soon as the first light reappears at the edge of the moon’s disc, you must put your glasses on immediately. For anyone observing north of the path of totality – that is, from the North Sea to the Côte d’Azur and the French Riviera – there is no such safe moment. In these areas, the glasses should be worn at all times.

What the DLR measures and how sailors benefit from it

The German Aerospace Centre (DLR) is using the solar eclipse for an international measurement campaign. The focus is on the ionosphere: when solar radiation is abruptly reduced by the Moon’s shadow, the electron density in the upper atmosphere changes significantly within a few minutes. GPS and Galileo signals pass through this layer and may be delayed as a result.

No specific GPS outages are forecast for the eclipse. DLR’s research is focused on developing better atmospheric models, not on issuing warnings. Anyone who knows how to continue navigating with a map and compass in the event of GPS disruptions will be well prepared, both on Wednesday evening and in general.

In the long term, these findings will also be incorporated into what is known as the R-Mode system which is designed to provide ships with a terrestrial position fix in the event of a satellite reception failure. The eclipse provides a clearly defined, reproducible test case for this.

Short-term weather impact possible

Within the path of totality, the air cools briefly during the lunar shadow. Observations from previous eclipses show temperature drops of several degrees Celsius, and in rare cases significantly more. These may be accompanied by brief changes in wind speed and humidity. These effects last only a few minutes and cannot be predicted.

For sailors, this means that a sudden change in wind direction or a lull cannot be ruled out. Anyone at anchor should keep a safe distance from the shore. This weather phenomenon does not pose any particular hazards.

Will you be out on the water on Wednesday evening – from the Baltic Sea to the Balearic Islands? Let us know in the comments where you’ll be watching and what the spectacle was like from on board.