The most reliable scuba window is May to October, with June, September, and early October usually the best balance. June has active operators, warm weather, and fewer peak crowds. September and early October often have warmer water after summer, good visibility, and easier topside temperatures. July and August are diveable and warm, but the Aegean Meltemi can force site changes, especially in the Cyclades and Dodecanese. Winter diving is possible with local operators in larger hubs, but expect cooler water, storms, and reduced island schedules.

Beginners should choose regions with sheltered coves, established dive schools, easy transfers, and non-diver backup plans. Good choices include Athens Riviera and Saronic Gulf, Crete's north coast, Rhodes east-coast bays, Kos around Kefalos and Kastri, Zakynthos south-coast operations, Corfu's Paleokastritsa area, and Halkidiki. Typical first dives use clear shallow water around 5 m to 12 m with instructor control. Avoid choosing a trip only for a named wreck or cavern if the group includes uncertified or nervous divers.

Choose the Aegean for volcanic landscapes, Cyclades ferry routes, Dodecanese warmth, Athens logistics, and strong archaeology. Choose the Ionian for greener islands, limestone caves, blue coves, turtle stories, and a slightly softer family-road-trip feel. The Aegean is more exposed to summer northerly wind, especially July and August, while Ionian plans still need attention to west-coast swell and storms outside summer. For a first trip, Athens plus one island is easier than trying to sample both seas. For caves and turtles, start Ionian; for ferries and culture, start Aegean.

Yes, if you expect Mediterranean clarity, coves, rocks, caves, seagrass, and beach scenery rather than tropical coral gardens. Strong snorkel regions include Zakynthos, Corfu, Kefalonia, Rhodes, Kos, Santorini, Naxos, Paros, Crete, Halkidiki, and Thassos. Most casual snorkeling sits in 1 m to 8 m of water, but boat trips may float above deeper blue. Wear water shoes for rocky entries and start early before wind and boat traffic build. In turtle areas, use operators that brief distance rules and do not crowd wildlife.

Turtle sightings are possible but should never be treated as guaranteed or chaseable. Zakynthos is the best-known visitor turtle region because Laganas Bay and the National Marine Park of Zakynthos protect loggerhead nesting beaches and marine zones. Crete, the Peloponnese, and other Greek nesting areas also matter. Nesting activity generally runs from mid-May into August, with hatchlings later in summer and early autumn. Keep at least 15 m from turtles, do not touch or feed them, avoid lights on nesting beaches, and follow park and operator rules.

Yes. The two most important visitor examples are Zakynthos and Alonissos. Zakynthos protects loggerhead turtle nesting beaches and Laganas Bay, so boating, anchoring, beach access, turtle watching, and speed behavior can be restricted by zone and season. Alonissos and the Northern Sporades protect monk-seal habitat and manage access in marine park zones, with scuba allowed only in specific areas. Greece also protects underwater antiquities nationwide. Even outside parks, use a no-touch rule, avoid anchoring on Posidonia seagrass, and choose operators that explain local rules before entering the water.

A 5mm wetsuit is the safest default for most Greece scuba trips, especially from May to October if you plan repetitive dives, caverns, walls, or deeper profiles. Warm-blooded divers may be comfortable in 3mm during late summer shallow dives, while spring, November, deeper wrecks, long boat days, and thermoclines may justify 5mm plus hooded vest. Sea temperatures vary by region and month, roughly from cool spring water around 16°C to warm late-summer water around 28°C in some areas. Snorkelers may prefer a rashguard in midsummer.

Wind is one of the main Greece planning variables. The Aegean Meltemi can bring clear skies but strong northerlies, especially from June through September and most noticeably in July and August. During active spells, winds may reach around 25 km/h to 45 km/h or more, enough to move dive sites, cancel exposed boats, or delay fast ferries. Operators usually know the lee shore and will adjust. Schedule early dives, avoid same-day ferry-to-dive plans, and give Cyclades or Dodecanese itineraries buffer days.

For ordinary recreational reef dives booked with a licensed dive center, travelers usually do not buy a national scuba permit. The important exception is protected underwater cultural heritage. Amphora fields, ancient wrecks, submerged ruins, and official accessible underwater archaeological sites are regulated. Some can be visited only on approved routes with licensed recreational diving providers and trained guides. Never touch, move, collect, or anchor on artifacts. Modern wrecks may also require specific operator permissions, conditions, and certification level. Ask the dive center exactly what is allowed before entering the water.

Use ATH for Athens Riviera, Saronic Gulf, Piraeus ferries, and flexible domestic connections. Use HER or CHQ for Crete depending on east, central, or west-coast plans. Use CFU, EFL, or ZTH for Ionian island trips to Corfu, Kefalonia, or Zakynthos. Use JTR, JMK, PAS, or JNX for Cyclades plans, often combined with ferries. Use RHO or KGS for Dodecanese diving, and SKG for Halkidiki, Thassos, and northern Greece. The best airport is the one closest to your dive operator, not just the cheapest fare.

Greece is very good for freediving when you plan around safety and wind. Kalamata is the most important depth-training and competition hub, while Zakynthos, Santorini, Crete, Kefalonia, Naxos, Paros, and Rhodes can offer clear recreational apnea, line sessions, and cave-light scenery with the right guide. The usual comfortable training window is June to October, with September especially attractive. Do not freedive alone, do not enter overhead caves on breath-hold, use a visible buoy, and ask schools about oxygen, safety divers, lanyards, and boat-traffic control.

Greece has experienced dive centers and modern medical infrastructure in larger cities and islands, but remote island logistics can slow specialist care. The safest plan is conservative profiles, local guides, a DSMB, no rushed flying, and insurance that covers recompression and evacuation. For suspected decompression illness, stop diving, give oxygen if trained and available, call 112 or 166, and contact DAN Europe. Hyperbaric and diving-medicine support is concentrated around major centers such as Athens and selected regional facilities, so do not treat emergency transport as instant from every island.

Yes, and Greece is one of the best countries for mixed groups. Athens pairs diving with the Acropolis, Lake Vouliagmeni, and Cape Sounio. Crete adds Knossos, Chania, Samaria Gorge, Spinalonga, food, and beaches. Cyclades routes add Delos, Akrotiri, caldera hikes, villages, and nightlife. Ionian islands add caves, turtle education, Venetian towns, and road trips. Rhodes and Kos add medieval streets, the Asclepieion, thermal springs, and easy beaches. The key is to schedule non-diver experiences deliberately rather than leaving them to fill time around dive boats.