Diving in Greece best-kept secret: Alonissos, Northern Sporades

I’m so delighted I can finally add Greece to my dive map whereas it was actually my third trip. The first time I celebrated my 12th birthday near Athens and I taught myself how to read Greek. I guess it was the trip that made me fall in love with travelling and language learning. After exploring Crete in 2003 and becoming a scuba diver in 2009, I was eager to go back to Greece scuba diving… but where?

Scuba diving was almost entirely forbidden in Greece until 2005 due to the risks towards its submerged archaeological patrimony. Rules became more flexible in 2006, which explains why the scuba diving industry is still very recent in Greece. While most people flock to Crete or the Cyclades, I got invited to explore a tiny island in the Northern Aegean Sea eager to spread the word about their divers’ paradise: Alonissos, in the archipelago of the Sporades. When I found out about its marine protected area, one of the largest in Europe, and how the island was protected from mass tourism, I immediately started organising my trip thanks to the direct flights of Thomas Cook Airlines between London Gatwick and Skiathos, a neighbour island of the same archipelago.


Alonissos National Marine Park

Alonnisos National Marine Park was created in 1992 and was Greece’s first marine protected area. It covers 2,260 km2  and includes seven islands, Alonissos, Peristera, Kyra, Panagia, Gioura, Psathoura, Piperi and Skantzoura, and 22 small islets. The park is divided into 3 zone A, B and C. Zone C, the core of the park is around Piperi Island and has the highest level of protection. This is where the endangered monk seals (Monachus monachus) live and breed. They can sometimes be seen around Alonissos, but this is rare. With about 700 individuals left in the entire Mediterranean Sea, monk seal is now the rarest seal on Earth. The colony of Alonissos National Marine Park counts between 55 to 60 individuals. It is sadly the biggest in the Mediterranean Sea. However, the fact they chose Alonissos National Park as their home shows the quality of the ecosystem.

MOm (Hellenic Society for the Study and Protection of the Monk seal) is the Greek non–profit organisation taking care of the protection of the Mediterranean monk seal. In 2016, after 25 years of efforts to preserve the species, the IUCN announced that the Mediterranean monk seal “stepped down” one category on the endangered species list, from “critically endangered” to “endangered”. Don’t hesitate to visit their information centre in the port of Patitiri.

You will need more than luck to hope to see a monk seal while in Alonissos. Please note that no tour is taking any visitor to see the monk seals. Piperi Island is strictly forbidden to be approached by any boat other than for scientific research purpose. Zone A is also strictly controlled: activities such as snorkelling tour or commercial fishing may be authorised if the management authority delivers a special permit but scuba diving is strictly forbidden. Zone B has the lowest level of protection which only includes a ban on wild camping and use of fire, with some areas where boat speed is limited. Still in zone B, the port authority doesn’t allow scuba diving everywhere: for example, the entire north shore of Alonissos is prohibited for scuba divers. Hopefully one day, we will be allowed to explore it with trained and authorised operators!

Map Alonissos NAtional MArine Park

While the monk seal is the star of Alonissos National Marine Park, the conservation effort also goes to cetaceans and the great biodiversity found around its islands. Four species of dolphins are regularly observed in the Park: the striped dolphin (Stenella coeruleoalba), the short-beaked common dolphin (Delphinus delphis), the bottlenose dolphin (Tursiops truncatus), and Risso’s dolphin (Grampus griseus). There have been sighting as well of Cuvier’s beaked whales (Ziphius cavirostris) and even a few sperm whales (Physeter macrocephalus)! The Northern Aegean Dolphin Project is a citizen science program conducted by MOm, aiming at recording encounters and behaviours such as social interactions of the different species of dolphins found in the park. If you are interested in marine conservation, you can join and become a marine conservation research assistant for a week (you can also hop just for a day).


My Greek island retreat in Alonissos

Even the most hard-core adventurers sometimes need a break! Yes, even if I’m usually all about road trips and crossing entire countries just to explore an extraordinary dive destination, I absolutely loved taking my 3h30 flight and my 1h30 ferry ride and just stay on the same island for a week. While I usually avoid European destinations at all cost in July and August, the promise of an out-of-the-beaten-track Greek Island, all about experiencing crystal clear waters, outdoors activities and embracing authentic Greek culture away from the crowds, definitely got me.

It was so funny how I quickly got used to my Alonissos routine. I woke up with sunrise at 6.30 am, prepared my Greek coffee at 8 am, and I was scuba diving from 9.30 am to 1.30 pm. After lunch and relaxing by the pool, writing and editing pictures, I was usually exploring the island between 5 and 8 pm to enjoy cooler temperatures (temperature was easily around 35°C around noon in August ). I could then enjoy a long Greek mezze dinner every night with my new friends of Triton Dive Centre! Alonissos is definitely one of these scuba divers island paradises that will make you come back, again and again.

Read my article about the 5 amazing things I did during my one week retreat in Alonissos.


Top 5 dive sites of Alonissos

In 8 days, I dedicated 1 day at the beginning and 1 day in the end for flying between London Gatwick and Skiathos and taking a ferry between Skiathos and Alonissos. Because of the 24 hours of non-diving safety before the return flight, I had 5 days of scuba diving left. One diving day had to be cancelled because of the strong winds one morning, but I took the opportunity to join the afternoon snorkelling trip to Skopelos Island which was just as awesome. So in 4 days, I dived 8 times in 7 different dive sites. Here is the selection of my 5 favourite dive sites during my 1-week holiday in Alonissos and which made it to my list of the best diving in Europe:

The Blue Cave

This is the dive site that amazed me the most in Alonissos thanks to its diversity. Wheather you are a beginner or an advanced scuba diver, if you like marine life or caverns, there is something for everyone at the Blue Cave. The dive boat stationed inside the Blue Cave which is actually a large open sea cavern but we started the dive by getting out to visit the nearby wall on the right side. You can go deeper if you want, but it was in the 15-20 m zone that I found the most interesting marine species in the numerous cracks covered in sponges and cup coral: nudibranchs, scorpionfish, groupers. The second part of the dive, we were very shallow between 5 and 10 m, to explore the different areas of the cave for some scenic views while doing our safety stop.

dive parameters: max depth 25,2 m – 54 minutes – water temperature 26°C


The Gorgonian Garden

I heard a lot of this dive site before finally diving there as it is one of the rare authorised dive sites in Alonissos where you can see so many beautiful red and yellow gorgonians. Unfortunately, because of the depth (you will need to be deep diver certified) and the currents, this dive site will be only for advanced and experienced divers. First, you need to swim a little while in the 25 m zone following the cliff on your left, and then you can see a pointed stripe of rock on your right: this is where the red gorgonian wall starts, below 35 m deep. From the moment I was on the wall, I knew I would have only a few minutes of non-decompression time to take my pictures. Maybe because of the stress and who knows some nitrogen narcosis, I had very few ones that were in focus, unfortunately. We started to ascend step by step, by visiting the other side of the wall which is covered in yellow gorgonians at about 30 m deep. We then went back to follow the cliff and did a long deep stop at 12/15 m before doing our final safety stop at 5 m. We both agreed with Martino, the instructor who was my buddy on this dive, that currents were moderates that day, but anyway, a good air consumption management is the key when you have both great depth and currents to manage.

dive parameters: max depth 41,4 m – 44 minutes – water temperature 26°C / 20°C at 30 m / 18°C at 40m


Agios Georgios South Reef

It was such a fun site to dive! Although you don’t need to go too deep on this site, the currents and different swim-through require scuba divers to be in perfect control of their buoyancy and to know how to fin kick efficiently. The dive site is made of two large pinnacles where you can find groupers, moray eels, scorpion fish and nudibranchs. At the beginning of the dive, we started by descending in a large chimney that conducts to a small sea cavern that is beautifully covered in sunset cup coral. Towards the end of the dive, this is where I saw the biggest moray eels of my diving trip in Alonissos.

dive parameters: max depth 26,7 m – 56 minutes – water temperature 26°C / 22°C at 25 m


Agios Petros Reef

I dived there twice, and each time we saw an adorable cuttlefish on the sandy bottom between the Posidonia seagrass patches. It’s also an excellent site to do macro underwater photography with many nudibranchs and striped blennies which like to stay in front of the camera! Towards the end of the dive site, before making your way back to the boat, you can find amphorae! Unfortunately, they are not genuine ancient amphorae but copies. There are actually archaeological sites around Alonissos, but these are at the moment heavily restricted and not allowed for scuba divers to explore. However, these amphorae still make a fantastic subject to photograph!

1st dive parameters: max depth 16,3 m – 48 minutes – water temperature 26°C

2nd dive parameters: max depth 14,5 m – 71 minutes – water temperature 26°C


Mourtias North Reef

Mourtias Reef has a wall part between 20 and 30 m deep, and a plateau part between 10 and 15 m deep. In the middle of the wall, we saw 3 big groupers. Mourtias Reef is famous for its big groupers. Unfortunately, they were so shy that I couldn’t take any decent picture or video of them. Fair enough, I think some animals really hate my video torchlight. Only one solution, I need to upgrade my photo gear and get a strobe! The plateau part was rich in nudibranchs feeding on sponges (spotted doris) or hydroids (flabellinas and hervias).

dive parameters: max depth 25,4 m – 43 minutes – water temperature 26°C / 25°C at 20 m


Who to go diving with in Alonissos, Greece?

The high scuba diving standards and the Greek hospitality of the team of Triton Dive Center were totally part of my relaxing scuba diving holiday in Alonissos. After the first day of bringing down all my gear from my hotel to the dive centre, every morning I just had to go to the boat directly in the port of Patitiri where my scuba babies would be ready and just waiting for me. Triton Dive Center host a crew of 2 instructors, 1 divemaster and 3 to 4 divemasters in training, so you’ll have plenty of help and people around you during the dive showing you cool stuff underwater. If you are travelling without any scuba diving equipment, you’ll be glad to know they have brand new rental gear, including 5mm full suit with boots and adjustable fins (top of the comfort for Mediterranean waters), and price of rental equipment is always included in the price of the dives. They do a 2-tank dive trip in the morning, and another 2-tank trip in the afternoon, so you can choose to dive all day long or share your time between scuba diving and exploring the beautiful island of Alonissos!

Dive & Stay packages start from 445€ for May and October, 465€ for June & September, and include 7 nights accommodation with 10 boat dives (rental equipment included). All prices details are on their website.

Alonissos Triton Dive Center


Waterfront, Patitiri, Alonissos 37005

Phone: +30-24240-65804




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Photo Credits: Alonissos National Marine Park map and pictures of monk seal and dolphins courtesy of MOm; pictures of me underwater by Martino of Triton Dive Center. Many thanks to Triton Dive Center & Thomas Cook Airlines for inviting me to discover this incredible Greek island underwater and beyond. As always, all my views and opinions are my own and reflect honestly my experience there. 


Scuba diving in Alonissos GreeceScuba diving in Alonissos Greece


Posted by Florine

  1. […] The Blue Cave will please all levels of divers who can explore its large open water sea cavern safely at shallow depths, while more advanced divers can explore its deeper wall to look for an abundant marine life in its cracks. The most adventurous divers holding a deep specialty and trained to drift diving will look forward the Gorgonian Garden between 35 and 40 m deep, one of the most densely covered in red gorgonians wall I have seen in the Mediterranean Sea. Read my complete guide to diving in Alonissos to check which dive sites are perfect for you. […]


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