【Taiwan Dive Sites】Strong-Current Diving Without Going Abroad — Penghu Southern Four Islands: The Wolf of Dongji

The Editor says: When it comes to Penghu dive sites, everyone's first instinct is to think of the Southern Four Islands — and when you think of the Southern Four Islands, you think of the ferocious currents! The Wolf of Dongji is one of the most well-known strong-current dive sites in Penghu's Southern Four Islands. But where there's strong current, there's fish — here you have a chance to see massive schools of yellowtail barracuda, and you might even run into a silvertip shark or a southern guitarfish! Strong currents? No sweat. This article is contributed by 徐志綸 (Lancehsu)

Penghu Southern Four Islands Dive Site — The Wolf of Dongji

On this dive, the current in the Wolf Zone was running at 1.5 knots. The barracuda were no longer hugging the bottom, and I was able to hold my camera steady and get close enough to photograph them properly. (Editor's note: According to the experience shared by Brother Ye of Island 77, once the current exceeds 2 knots, the barracuda will be pushed down to the bottom by the force of the water, making it impossible to capture the spectacular sight of a baitball storm.)

Tides are generated by the gravitational forces produced by the relative positions of the sun, Earth, and moon. Because tidal cycles are fixed, scientists can predict the timing and direction of incoming and outgoing tides well in advance.

In nautical terms, current distance and speed are measured in "nautical miles and knots." The Kuroshio Current along Taiwan's east coast can reach 3–4 knots in summer and 2–3 knots in winter, while coastal currents typically run at 1–2 knots — which is why so few people dive off Taitung or Hualien. It's not that it never happens, but the risk is extremely high. At 1 knot, water travels 30.8 metres per minute, or 1.852 kilometres per hour; one nautical mile equals 1,852 metres.

1.5 Knots: A Relaxed Dive

The Wolf Zone is one of the most telling places to feel the current at work. Below 1.5 knots, conditions usually correspond to neap or moderate tides. The barracuda move in tight, coordinated schools. You can still swim slowly into the current, and when you need to hold your position, a gentle grip on the reef is all it takes.

2 Knots: Your Heart Will Start Pounding

At 2 knots — typically during a moderate tide — a diver fighting the current might just barely hold position for about 10 seconds. After that, the strength drains fast and you'll find yourself drifting further and further from the group. It's also easy to start hyperventilating. For beginners or anyone who has never dealt with current before, this is a serious challenge.

2.5 Knots: You'll Only Catch a Fleeting Glimpse of the Barracuda

When the current reaches 2.5 knots, even swimming hard in carbon-fibre long fins (freediving), I can barely hold position for 10 seconds. You have to grab onto the reef. Let go and drift, and you'll likely be swept out of the Wolf Zone in under 10 minutes — and the wolf pack will be gone from sight.

3 Knots: Bring Every Trick You Have — It's Going to Be Wild

At 3 knots, you're usually in spring tide territory. Your second stage regulator may start free-flowing heavily; if you're not facing into the current, water will flood straight in. Your surface marker buoy (SMB) could get blown open unexpectedly. No matter how many times you clear your mask, water keeps rushing back in. Air consumption will be far higher than normal. At this point, your dive guide, instructor, and dive buddy may all be fully occupied dealing with their own situations. If you can't resolve these basic problems on your own underwater, you could be in very serious danger.

For this reason, dive shops operating in the Southern Four Islands typically require divers to hold at least an Advanced Open Water Diver (PADI cert) certification with a minimum of 50 logged dives. Anything less and you're punching above your weight — proceed at your own risk.

A boat captain's most fundamental duty is to understand the tides. If the dive instructor also understands tidal patterns, they can anticipate current direction and predict where marine life is likely to appear. When the captain and instructor work together with a shared understanding of the tides, they can bring you safely through demanding conditions — and reveal an underwater world you'd never see otherwise.

Related links:

• 徐志綸 (Lancehsu) Personal Facebook
• 徐志綸 (Lancehsu) Instagram
• Island 77
• Diving in Current! What to Do When You Encounter Washing-Machine Currents, Downwellings, or 3-Knot Flows? 6 Dive Safety Tips You Should Know