SS Reina del Mar - Alonissos Marine Park

Diving the HMS Formidable is a true journey into a piece of naval history, a sobering reminder of wartime losses. We typically approach this site when the tides are slack, making the descent more manageable, though you can still feel the pull around the deeper sections. What we love about the Formidable isn't just its size, though it's impressive, but the way the ocean has truly claimed it. You’ll find her spread across the seabed, broken into several large sections. Dropping down, the first thing you notice is the sheer scale of the hull plates and the massive gun turrets, now heavily encrusted. Schools of whiting often flicker through the darker interior spaces, and we’ve spotted impressive conger eels lurking in the deeper, more sheltered corners. The elegant cuttlefish are a frequent sight here too, their colours shifting as you pass. Our favourite part is navigating through the collapsed superstructure, where you can often spot thornback skates resting on the sand patches between debris. This dive is best for experienced wreck divers comfortable with colder water and potentially low visibility; it’s a proper exploration, not a gentle drift. Bring a good torch and take your time.

Location: Alonissos Marine Park, Greece, Mediterranean & Europe
Coordinates: 37.950000, 23.550000
Type: wreck

Marine Protected Area: NISIDES SARONIKOU KOLPOU KAI THALASSIA PERIOCHI

Best Time to Dive in Alonissos Marine Park

The warmest water temperatures in Alonissos Marine Park occur in August, averaging 27.2°C. The coolest conditions are in February at 13.9°C.

Monthly Water Temperatures

January: 14.5°C
February: 13.9°C
March: 14.2°C
April: 15.4°C
May: 18.7°C
June: 23.5°C
July: 26.5°C
August: 27.2°C
September: 25.3°C
October: 22.8°C
November: 19.9°C
December: 16.9°C

Nearest Dive Centres to SS Reina del Mar

Marine Life in Alonissos Marine Park

Home to 16 recorded species including 3 whales & dolphins, 3 reef fish, 2 other, 2 hard corals, 2 crabs & lobsters, 1 seagrass & algae.

Notable Species

loggerhead turtle (Caretta caretta)
Blue-white Dolphin (Stenella coeruleoalba) - Whales & Dolphins
Leidy's Comb Jelly (Mnemiopsis leidyi)
Cowfish (Tursiops truncatus) - Whales & Dolphins
Marbled Spinefoot (Siganus rivulatus) - Reef Fish
Silver-cheeked Toadfish (Lagocephalus sceleratus) - Reef Fish
Devonshire cup coral (Caryophyllia (Caryophyllia) smithii) - Hard Corals
Species code: Hs (Halophila stipulacea) - Seagrass & Algae
Short-beaked Common Dolphin (Delphinus delphis) - Whales & Dolphins
Norway Lobster (Nephrops norvegicus) - Crabs & Lobsters
Red coral (Corallium rubrum) - Soft Corals
Bottleneck Sea Cucumber (Holothuria (Thymiosycia) impatiens) - Sea Cucumbers
Sand mason (Lanice conchilega) - Worms
Bushy Coral (Cladocora caespitosa) - Hard Corals
Wrasse (Coris julis) - Reef Fish
Blue Crab (Callinectes sapidus) - Crabs & Lobsters

Recommended Packing List for SS Reina del Mar

Based on average water temperature of 19.9°C, currents 3 cm/s.

Wetsuit (3-5mm) - comfortable for 20°C water
Mask - essential for every dive
Fins
BCD - buoyancy compensator
Regulator - your most safety-critical piece of gear
Dive Computer - tracks depth, time, and NDL
Surface Marker Buoy (SMB) - essential for boat pickups
Dive Torch - useful for crevices and colour at depth
Underwater Camera - capture your diving memories