Advanced Zone · Wall Dive · Dwejra, Gozo

Blue Hole

A natural limestone pool at Dwejra Bay, Gozo, connected to the open sea through an underwater arch at 9 metres. Beyond the arch, a dramatic wall drops past 60 metres into the deep blue.

36°03'10"N · 14°11'39"E | Dwejra Bay, Gozo

40m

Rec Limit

Arch Depth

60m+

Wall Drop

20–30m

Visibility

Adv OW

Min Cert

18–27°

Temp

Site Profile

History & Geology

Ancient

The limestone cliffs at Dwejra were shaped over thousands of years by wave action and marine erosion. The Blue Hole formed as the roof of a sea cave collapsed, leaving a circular pool open to the sky and connected to the sea below the waterline.
1980s

Dwejra Bay, already renowned for the Azure Window arch and the Inland Sea, was formally recognised as a prime dive destination. The Blue Hole became Gozo's signature dive, attracting divers from across the Mediterranean.
2008

Dwejra designated a Special Area of Conservation under Malta's Environment Protection Act, with marine protection extended to the reef and wall system around the Blue Hole.
2017

On 8 March 2017, the Azure Window, the iconic natural limestone arch adjacent to the Blue Hole, collapsed into the sea during a storm. The fallen columns now form an additional underwater feature at 20–28 metres.
Today

Consistently rated one of the world's top 10 dive sites. The wall, arch, and chimney draw technical and recreational divers year-round. The Azure Window collapse has added a new dive within the same bay.

The Blue Hole itself is roughly 10 metres in diameter and 15 metres deep. Its roof is open to the sky, making it recognisable from the surface before you even kit up. At 9 metres depth, a natural arch in the rock wall connects the pool to the open sea. Step through this arch and the seabed disappears beneath you, the wall drops vertically past 60 metres, covered in gorgonian fans, red and orange sponges, and dense populations of anthias. The Chimney, a vertical crack in the rock to the right of the arch, offers a spectacular ascent from around 20 metres back up to 5 metres. The fallen remnants of the Azure Window lie on the sandy bottom to the south at 20–28 metres, now colonised by marine life.

Points of Interest

What to Explore

The Arch

The heart of the Blue Hole experience. At 6 metres, the pool wall opens into a wide natural arch connecting the sheltered pool to the open sea. The contrast, sheltered limestone pool behind you, infinite blue wall ahead, is one of diving's most dramatic transitions.

5 – 22m

The Chimney

A vertical crack in the rock running from about 22 metres back up to 5 metres, emerging on the pool side. Swim it from below, ascending through the narrowing crack as light filters down from above. One of the most memorable underwater passages in the Mediterranean.

18 – 40m+

The Wall

Beyond the arch, a sheer limestone face drops vertically past 60 metres. Covered in massive gorgonian sea fans, orange sponges, black sea whips, and clouds of anthias, it is Malta's finest wall dive. Recreational divers work the 18–40 metre range; tec divers descend further.

20 – 28m

Azure Window Remains

Since the 2017 collapse, the fallen columns and arch remnants of the Azure Window lie on the sandy seabed south of the Blue Hole at 20–28 metres. Now colonised by marine life, the debris field makes a fascinating secondary dive on the same entry.

Diving Conditions

When to Dive

Season	Conditions	Temp	Vis	Rating
Jan – Mar	Exposed site. NW swells can make entry dangerous. Dive on calm days only. Excellent clarity when diveable.	15-17°C	20-30m	Fair
Apr – Jun	Conditions improve rapidly. Water warming. Strong spring swell possible in April. Good from May onward.	17-22°C	20-30m	Good
Jul – Sep	Peak season. Flat calm seas most days. Exceptional clarity. Warm water throughout. Best for the wall dive.	24-28°C	25-35m	Peak
Oct – Dec	Excellent conditions through October. November brings NW swells. Water cools but remains crystal clear.	18-24°C	20-30m	Good

Average Visibility

Jan – Mar

22m

Apr – Jun

26m

Jul – Sep

30m

Oct – Dec

25m

Site Conditions

Dwejra is an exposed west-facing site, open to NW and SW swells. When conditions are good, it offers some of the clearest water in the Mediterranean, 25–35 metres visibility is common in summer. When conditions are poor, surf breaks directly on the entry steps and the dive should be postponed. Always check the swell forecast before travelling from Malta to Gozo. Current at the arch can be noticeable, particularly on ebb tide. A torch is useful but not essential. Nitrox is strongly recommended for the wall dive to extend bottom time.

Entry

Shore entry via steps cut into the limestone at Dwejra Bay. Enter into the Blue Hole pool, descend to the arch, then exit to the open water. Exit the same way or swim around the outside to the beach in calm conditions. Rough seas close this site.

Swell & Current

A west-facing exposed site. Check NW swell forecasts before diving. 1m+ swell makes entry dangerous. Current through the arch is typically mild but can pick up with shifting currents. Plan your dive to return through the arch upcurrent.

Depth Planning

The wall is effectively limitless, your certification and gas planning determine your depth. Recreational divers: plan to 30m maximum. Advanced divers: 40m limit on air. Tec divers may proceed deeper with appropriate training and gas. No-deco time at 30m on air is approximately 20 minutes.

Safety & Requirements

Before You Dive

Advanced OW

Certification

Advanced Open Water minimum recommended for the wall and arch dive. Open Water divers may explore the Blue Hole pool (0–15m) with a guide. The Chimney and wall require Advanced certification. Technical dives below 40m require full tec training.

Conditions Check

Always Check Swell

Dwejra is exposed to Atlantic swells. Do not attempt entry in swell above 1 metre. Check Windguru or Windy for the WNW and NW swell forecast. The site can look calm from the road while surf breaks at the steps. Your guide will make the final call on entry.

Gas Planning

Nitrox 32% strongly recommended for extended wall time. At 30m on air, no-deco limit is approximately 20 minutes. Plan your deepest point first (wall), then ascend along the wall to the arch level for decompression margin. Bring a DSMB for surfacing if separated.

Buoyancy

Buoyancy on the Wall

The wall offers no easy reference for depth, it's easy to exceed your planned depth without noticing. Set your maximum depth on your computer before descending. Watch your gauge constantly. Slow and controlled buoyancy is essential on any wall dive.

Arch Passage

Arch & Chimney

The arch is wide and unrestrictive. The Chimney narrows toward the top, divers with doubles or side-mount should check their width before entering. Never enter any overhead environment without overhead environment training and appropriate redundant lighting.

Emergency

Gozo General Hospital (Victoria / Rabat): approximately 12 minutes by road from Dwejra. Mater Dei hyperbaric chamber (Malta): accessible via Gozo ferry. Emergency: 112. DAN Europe: +39 06 4211 5685. A surface tender is advised for any deep wall dive.

Book This Dive

Dive the Blue Hole with diveshack

We run guided trips to the Blue Hole from our Gozo base in Marsalforn and from Sliema via the Gozo ferry. Our guides know every metre of the arch, chimney, and wall. Conditions-dependent scheduling, we monitor swell forecasts daily and will reschedule if Dwejra is unsafe.

Departs Marsalforn, Gozo (or Sliema with ferry)

Duration Approx. 50–65 min dive + briefing

Group Size Max 5 divers per guide

Cert. Req. Advanced Open Water (wall dive)

Includes Guide, weights, conditions assessment, full briefing

Add-on Nitrox fills, Azure Window wreck dive extension

WhatsApp Us Email Us +356 9999 3483

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Blue Hole

History & Geology

What You Might See

Mediterranean Fairy Basslet

Dusky Grouper

Yellow Gorgonian

Jewel Anemone

Greater Amberjack

Conger Eel

Mediterranean Feather Star

Violet Sea Urchin