The Poseidonion Hotel was built by Sotirios Anargyros, descendant of a great 18th-century Spetsiot shipping family.
His branch of the family had fallen on hard times, and he emigrated to the United States as a young man in 1868, when Spetses was declining as a maritime center.
In 1899 he returned from the US, now a wealthy tobacco tycoon and started to transform the island of his youth.
He built an impressive mansion and met with rich Athenians who visited Spetses from August to October, in order to hunt the turtledoves and quail migrating between Africa and Europe.
Anagyros had pine seedlings planted in the hills.
In the early 21st century, the island is one of the most wooded in the southern Aegean.

He saw the need for a comfortable hotel and built the Poseidonion in the style of its French Mediterranean models, the Carlton in Cannes (1911) and the Negresco in Nice (1912).
The hunters could bring along their wives and children to enjoy the comfort of the hotel, the spa, donkey rides, dancing to the orchestra in the evening, and mixed bathing on the beaches across the channel.
The Poseidonion rapidly became the favorite vacation spot for high society, royalty, and the rich Athenians who came to enjoy a small slice of the grand life.

In the 1960s and 1970s, the island attracted a number of wealthy Greek vacationers from Athens and elsewhere, who owned second villas or lived on their large yachts in the port.
Some had children who became students of the Anargirios School.
Although some hotels had been constructed, tourists often stayed in purpose-built holiday homes.
From the 1980s, the Greek vacationers were often supplanted by north European tourists, especially from Britain, who were attracted by the low cost of a holiday.

Package tours to Spetses declined and eventually ceased during the 1990s.
In the early 21st century, the island's holiday clientele is of a higher economic class and largely Greek.

"Spetses is where superyachts bob up and down next to traditional wooden fishing boats and where the super-rich rub shoulders with the locals in quayside tavernas.
 All are drawn to this pine-covered island for its secluded coves and clear waters and the glories of Spetses Town, the island hub, untainted by package tourism."

The main Athenian tourist season lasts for only two months of the year, although most hotels and restaurants are open from Easter until October.
Efforts are being made by officials to extend the season, by adding major events to attract visitors:
The Spetses Classic Yacht Regatta
In June a weekend of sailing races, starting/finishing in the straight between Spetses and Kosta.
A record number of 75 yachts took part in the 2015 Regatta, which celebrated its 5th anniversary; categories were Vintage (built prior to 1947), Classic (built between 1948–1974), Spirit of Tradition (built after 1976), Traditional Caiques and Open Boats.

The Spetses Mini Marathon
The main event is an international 26 km (16 mi) marathon around the Island.
A 10 km (6 mi) race was added to the program in 2014.
The mini marathon has been held since 2011.
Swimming races of 2.5 km (1.6 mi) and 5 km (3 mi) have been added, as well as a children’s 1000 m. Running and swimming races are also part of the three-day program.
More than 2,000 men and women participate in the running events, while over 3,000 athletes in total take part in all sports.
According to the Greek press, this has become the biggest annual sporting event in Greece outside of Athens.

In September 2013, Dr Marina Lyda Coutarelli, President of the Organizing Committee and CEO of Communication Lab, was named "Honorary Citizen" of Spetses island.
She was honored for her work and effort, with regard to the island's development.

In the early 21st century, there was a distinct shift away from package tourism on Spetses and the island once again became fashionable amongst the wealthier Greeks.
Nowadays, the majority of visitors are Greek or independent travellers from around the world.
Whilst it is still possible to find traditional lower cost rooms to rent and tavernas to eat
The Poseidonion Hotel was built by Sotirios Anargyros, descendant of a great 18th-century Spetsiot shipping family. His branch of the family had fallen on hard times, and he emigrated to the United States as a young man in 1868, when Spetses was declining as a maritime center. In 1899 he returned from the US, now a wealthy tobacco tycoon and started to transform the island of his youth. He built an impressive mansion and met with rich Athenians who visited Spetses from August to October, in order to hunt the turtledoves and quail migrating between Africa and Europe. Anagyros had pine seedlings planted in the hills. In the early 21st century, the island is one of the most wooded in the southern Aegean.
He saw the need for a comfortable hotel and built the Poseidonion in the style of its French Mediterranean models, the Carlton in Cannes (1911) and the Negresco in Nice (1912). The hunters could bring along their wives and children to enjoy the comfort of the hotel, the spa, donkey rides, dancing to the orchestra in the evening, and mixed bathing on the beaches across the channel. The Poseidonion rapidly became the favorite vacation spot for high society, royalty, and the rich Athenians who came to enjoy a small slice of the grand life.
In the 1960s and 1970s, the island attracted a number of wealthy Greek vacationers from Athens and elsewhere, who owned second villas or lived on their large yachts in the port. Some had children who became students of the Anargirios School. Although some hotels had been constructed, tourists often stayed in purpose-built holiday homes. From the 1980s, the Greek vacationers were often supplanted by north European tourists, especially from Britain, who were attracted by the low cost of a holiday.
Package tours to Spetses declined and eventually ceased during the 1990s. In the early 21st century, the island's holiday clientele is of a higher economic class and largely Greek.
"Spetses is where superyachts bob up and down next to traditional wooden fishing boats and where the super-rich rub shoulders with the locals in quayside tavernas.  All are drawn to this pine-covered island for its secluded coves and clear waters and the glories of Spetses Town, the island hub, untainted by package tourism."
The main Athenian tourist season lasts for only two months of the year, although most hotels and restaurants are open from Easter until October. Efforts are being made by officials to extend the season, by adding major events to attract visitors:
The Spetses Classic Yacht Regatta
In June a weekend of sailing races, starting/finishing in the straight between Spetses and Kosta. A record number of 75 yachts took part in the 2015 Regatta, which celebrated its 5th anniversary; categories were Vintage (built prior to 1947), Classic (built between 1948–1974), Spirit of Tradition (built after 1976), Traditional Caiques and Open Boats.
The Spetses Mini Marathon
The main event is an international 26 km (16 mi) marathon around the Island. A 10 km (6 mi) race was added to the program in 2014. The mini marathon has been held since 2011. Swimming races of 2.5 km (1.6 mi) and 5 km (3 mi) have been added, as well as a children’s 1000 m. Running and swimming races are also part of the three-day program. More than 2,000 men and women participate in the running events, while over 3,000 athletes in total take part in all sports. According to the Greek press, this has become the biggest annual sporting event in Greece outside of Athens.
In September 2013, Dr Marina Lyda Coutarelli, President of the Organizing Committee and CEO of Communication Lab, was named "Honorary Citizen" of Spetses island. She was honored for her work and effort, with regard to the island's development.
In the early 21st century, there was a distinct shift away from package tourism on Spetses and the island once again became fashionable amongst the wealthier Greeks. Nowadays, the majority of visitors are Greek or independent travellers from around the world. Whilst it is still possible to find traditional lower cost rooms to rent and tavernas to eat 
Spetses