HMS Thetis - Ustica

Sykes Reef feels like diving into a moody, kelp-draped cathedral. We love this site for its sheer wildness, a true taste of the Pacific Northwest. Forget sun-drenched corals, here it's about the dramatic deep greens and blues, and the incredible, often gigantic, invertebrates. We've spent dives just watching Sunflower stars slowly patrol the rocky ledges, sometimes finding Spiny Dogfish lurking in the shadows. Look closely in the crevices and you'll spot Roughpatch shrimp and the occasional Plainfin midshipman. The currents can be lively, so this is definitely one for divers comfortable with a bit of a push, and good buoyancy control is key to navigating the kelp forests without getting tangled. Our favorite time to dive here is on a slack tide, right as the light starts to filter through the surface, illuminating the swaying kelp. You get these incredible shafts of light, almost tangible, cutting through the water. Keep an eye out for Red Rock crabs scuttling away, and we’ve even been lucky enough to hear Orcas pass overhead – a truly spine-tingling experience even if you don't see them. This site suits divers who appreciate a rugged, vibrant cold-water environment and don't mind trading tropical warmth for dramatic marine life encounters.

Location: Ustica, Italy, Mediterranean & Europe
Coordinates: 38.250000, 13.250000
Type: reef

Marine Protected Area: Area naturale marina protetta Capo Gallo - Isola delle Femmine

Best Time to Dive in Ustica

The warmest water temperatures in Ustica occur in January, averaging 15.5°C. The coolest conditions are in December at 15.5°C.

Monthly Water Temperatures

January: 15.5°C (air: 13.6°C)
February: 15.5°C (air: 13.5°C)
March: 15.5°C (air: 13.6°C)
April: 15.5°C (air: 15.0°C)
May: 15.5°C (air: 18.5°C)
June: 15.5°C (air: 22.7°C)
July: 15.5°C (air: 26.4°C)
August: 15.5°C (air: 27.0°C)
September: 15.5°C (air: 24.9°C)
October: 15.5°C (air: 21.6°C)
November: 15.5°C (air: 18.6°C)
December: 15.5°C (air: 15.3°C)

Nearest Dive Centres to HMS Thetis

Marine Life in Ustica

Home to 63 recorded species including 41 reef fish, 4 whales & dolphins, 3 other, 3 hard corals, 3 crabs & lobsters, 2 seagrass & algae.

Notable Species

loggerhead turtle (Caretta caretta)
Salema (Sarpa salpa) - Reef Fish
Wrasse (Coris julis) - Reef Fish
Ornate Wrasse (Thalassoma pavo) - Reef Fish
Painted Comber (Serranus scriba) - Reef Fish
Dusky grouper (Epinephelus marginatus) - Reef Fish
mauve stinger (Pelagia noctiluca) - Jellyfish
Blue-white Dolphin (Stenella coeruleoalba) - Whales & Dolphins
Damsel fish (Chromis chromis) - Reef Fish
Scarlet Coral (Balanophyllia (Balanophyllia) europaea) - Hard Corals
Garrupa (Serranus cabrilla) - Reef Fish
Bushy Coral (Cladocora caespitosa) - Hard Corals
Parrotfish (Sparisoma cretense) - Reef Fish
Mediterranean tapeweed (Posidonia oceanica) - Seagrass & Algae
Sunset cup coral (Leptopsammia pruvoti) - Hard Corals
Common Spiny Lobster (Palinurus elephas) - Crabs & Lobsters
Yellow Barracuda (Sphyraena viridensis) - Reef Fish
Pink Sea Fan (Eunicella verrucosa) - Soft Corals
Boarfish (Capros aper) - Reef Fish
Bellowfish (Macroramphosus scolopax) - Reef Fish

Recommended Packing List for HMS Thetis

Based on average water temperature of 15.5°C.

Wetsuit (5-7mm) - recommended for 15°C water
Hood & Gloves (3-5mm) - helps retain warmth
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