Greek islands are generating the bulk of the country’s tourism spending, but a new report highlighted by OT suggests that the same growth model is pushing several destinations beyond key pressure thresholds, deepening economic dependence and reshaping local landscapes.

The third report by the Sustainable Tourism Observatory for the Aegean Islands finds that the main island regions absorb about 60% of Greece’s total tourism spending, while destinations such as Santorini, Mykonos and Salamina record some of the country’s highest tourism-density levels. The findings point to a widening imbalance: tourism remains an economic lifeline, but also a source of mounting pressure on infrastructure, land use, housing and local economies.

The report, which is to be presented by University of the Aegean emeritus professor and Observatory director Yiannis Spilanis at the Hellenic Society for the Environment and Cultural Heritage, examines the changing profile of island tourism through indicators including tourist beds, short-term rentals, vacant homes, second residences, construction activity, income and social conditions.

A key benchmark is tourism density — the number of beds per square kilometer. According to the report, the European Environment Agency estimates the acceptable threshold of tourism pressure at 100 beds per square kilometer, a level already exceeded across much of the Aegean and Ionian islands.

Santorini, Salamina and Mykonos Lead the Pressure Index

Santorini records the highest overall pressure, reaching 1,164.4 beds-residents per square kilometer when tourist beds, holiday homes and permanent population are counted together.

It is followed by Salamina with 1,103.8, Mykonos with 759, Skiathos with 589, Aegina with 574, Spetses with 573 and Poros with 554. Only 22 islands record an overall density below 100.

Salamina’s position is striking because it is not a classic tourism destination. Its high ranking reflects the strong presence of second homes, showing that island pressure is not limited to globally known destinations such as Santorini and Mykonos.

In the lower-pressure scenario, which includes professional accommodation and short-term rentals through platforms such as Airbnb, several islands exceed 200 beds per square kilometer. Thira reaches 863.4 beds per square kilometer, Mykonos 611.4, Skiathos 381.5, Koufonisi 278.4, Paxos 245.9, Kos 232.5 and Poros 217.8.

The picture becomes more intense in the higher-pressure scenario, which also includes vacant homes used for short-term or long-term rentals, second homes or holiday residences. Under this measure, 21 islands exceed 200 beds per square kilometer. Thira reaches 964, Salamina 712, Mykonos 634.3, Skiathos 477.2, Aegina 418.3, Poros 409.8 and Spetses 404.4.

The findings suggest that pressure is spreading beyond the Cyclades. The Saronic Gulf, including Salamina, Aegina, Poros and Spetses, also faces significant strain, largely because of second-home development.

Islands Capture Most Tourism Spending

The pressure comes alongside deepening economic dependence. The report shows that the South Aegean alone accounts for 27.6% of Greece’s total tourism receipts, followed by Crete with 22.2%.

Together, the three main island regions absorb 59.4% of the country’s total tourism spending. That figure rises to 60.4% when the North Aegean is included.

Tourism spending is also high by national standards. Crete records the highest spending per trip, at 941.1 euros, followed by the South Aegean at 767.3 euros. The South Aegean also records the highest daily per capita tourism spending, at 105.5 euros in 2023, compared with a national average of 86.6 euros.

But the report notes that per capita spending has not shown substantial improvement over the past 20 years, despite the upgrading of much of the hotel stock into four- and five-star units.

Growth Built on a Narrow Base

The report also points to the risk of one-dimensional development. In the Dodecanese, 33.9% of Gross Value Added comes from accommodation and food services. In Attica, the equivalent figure is just 4.5%.

That contrast highlights how heavily some island economies rely on tourism-related sectors. The report suggests that while tourism generates revenue and employment, it also makes local economies more exposed to seasonality and fluctuations in visitor demand.

This dependence is visible in unemployment patterns. In some island regions, unemployment exceeds 20% in the first quarter of the year and falls below 5% at the height of the tourism season. On an annual basis, the Ionian Islands recorded unemployment of 14.8% in 2023, above the national average of 11%. The South Aegean recorded 7.2%, the North Aegean 9.8% and Crete 10.8%.

Construction Is Changing Island Landscapes

The report finds that tourism growth is not only changing local economies, but also the physical geography of the islands.

Based on the latest available Corine data for 2018, the Ionian Islands and the South Aegean are among the regions with the largest built-up areas in Greece, exceeding the national average of 2.95%. The figure reaches 5.05% in the Ionian Islands and 3.7% in the South Aegean.

At island level, Salamina is the most built-up island in the country, with 34.2% of its area built up. It is followed by Mykonos with 24.3%, Santorini with 20.2%, Syros with 15.5%, Aegina with 11% and Corfu with 8.4%.

Construction activity continues to accelerate. According to 2024 data cited in the report, 27% of the total surface area of new buildings in Greece was constructed in island regional units, although the islands account for only 19% of the country’s total land area.

For the report, this shows that tourism development is transforming not only island economies, but also their landscapes.

Second Homes Add to Tourism Pressure

The report divides islands into three broad categories according to the composition of available beds.

The first includes hotel-based islands such as Kos, Rhodes, Zakynthos and Corfu, where organized accommodation dominates and hotel beds exceed 60%.

The second includes islands where rented rooms and homes are dominant. These include smaller islands such as Kimolos, Irakleia, Sikinos, Kythnos, Anafi, Ithaca and Paxos, as well as major destinations such as Paros, Lefkada, Kefalonia, Naxos and Thira.

The third category consists of islands where second homes outweigh organized tourism infrastructure. Salamina reaches 99.8% in this category. High shares are also recorded in Mykonos at 90%, Thira at 77%, Koufonisi at 70%, Milos at 50% and Paros at 43%.

This helps explain why some islands that are not always associated with mass tourism still appear among the most pressured areas in the report.

Tourists Can Outnumber Residents Several Times Over

The imbalance becomes clearer when beds are measured against the permanent population.

Koufonisi records 3.5 professional beds per resident, followed by Schoinousa with 3.3 and Mykonos with 3.3. When short-term rentals are included, Mykonos rises to 4.9 beds per resident, Thira to 4.3 and Koufonisi to 4.1.

In the broader scenario, which includes professional beds and beds in vacant homes, Serifos reaches 8 beds per resident, Schoinousa 6.8, Antiparos 6.4 and Kastos 6. In total, 38 islands exceed three beds per resident, while another 60 exceed two beds per resident.

Cruise tourism adds further daily pressure. Santorini recorded 1,298,968 visitors by sea in 2023, compared with 742,553 in 2014, and has seen days with more than 10,000 cruise visitors. Mykonos recorded 1,192,822 cruise visitors, Corfu 667,182 and Rhodes 453,832.

When the high season is calculated as lasting four months, the report finds that on islands such as Mykonos and Santorini, the daily number of tourists can be more than three times higher than the number of residents.

High Revenues, Uneven Social Outcomes

The report also suggests that tourism growth has not automatically strengthened social cohesion.

The risk of poverty and social exclusion remains high in several island regions. It reaches 30.4% in the North Aegean and 27.7% in the Ionian Islands, both above the national average of 26.1%.

Income levels also vary sharply. Mykonos records an average income of 19,494 euros per tax return, followed by Thira with 18,062 euros and Paros with 16,915 euros. High figures are also recorded in Milos and Kimolos, as well as islands with strong shipping activity such as Psara and Chios.

Even so, only seven islands exceed the national average income of 13,962 euros.

Education indicators are also a concern. According to the report, the share of residents with tertiary education remains below the national average in all island regions, while early school-leaving is almost double the national average.