The Yellow Sea is bordered by three countries: China, North Korea, and South Korea. That’s the short answer most people came here for.
The longer answer is more interesting. This is a shallow, semi-enclosed arm of the Pacific wedged between mainland China and the Korean Peninsula — and those three countries don’t just share a coastline, they share fishing grounds, overlapping maritime claims, and some of the busiest ports in East Asia. The water itself gets its name from the silt that the Yellow River and other rivers dump into it, which can turn the surface a genuine golden-brown after heavy rains.
Table of Contents
- Quick Facts
- China
- North Korea
- South Korea
- Where the Borders Get Complicated
- Yellow Sea vs. Bohai Sea vs. East China Sea
- Frequently Asked Questions
Quick Facts
| Feature | Detail |
|---|---|
| Bordering countries | China, North Korea, South Korea |
| Area | ~380,000 km² (~147,000 sq mi) |
| Maximum depth | ~152 m (~500 ft) |
| Average depth | ~44 m (~144 ft) |
| Alternate names | Huang Hai (黄海, “Yellow Sea”) in China; Seohae / West Sea (서해) in Korea |
| Connects to | The Bohai Sea to the northwest, the East China Sea to the south |
| Major rivers feeding it | Yellow River (Huang He), Yangtze (via the East China Sea), Han, Yalu |
Worth knowing: the Yellow Sea is genuinely shallow for a body of water its size. At an average depth of around 44 meters, much of it was dry land during the last ice age, when sea levels were roughly 120 meters lower. China and Korea were connected by a walkable plain right where the sea now sits.
China
China holds the entire western and northern shoreline of the Yellow Sea, by far the longest coastline of the three. The provinces fronting it — Shandong, Jiangsu, and parts of Liaoning — anchor a chain of ports that move a serious share of the country’s seaborne trade.
The heavy hitters:
- Qingdao — Shandong’s flagship port and one of the busiest container terminals in the world. Also the city behind Tsingtao beer, a holdover from the German concession that ran here from 1898 to 1914.
- Dalian — sits up on the Liaodong Peninsula at the gateway between the Yellow Sea and the Bohai Sea. A major oil and container hub.
- Tianjin — technically on the Bohai Sea, the Yellow Sea’s northern pocket, and the maritime gateway to Beijing.
- Lianyungang — Jiangsu’s main Yellow Sea port and the eastern terminus of the New Eurasian Land Bridge rail corridor that runs all the way to Rotterdam.
China’s stake here is straightforward: the Yellow Sea is its front door to maritime trade with Korea and Japan, and a critical fishing ground. It’s also where the silt that names the sea originates. The Yellow River carries one of the highest sediment loads of any river on Earth, and that suspended sediment is what tints the water.
North Korea
North Korea’s west coast runs along the northern Yellow Sea, from the mouth of the Yalu River — the border with China — down to the disputed waters near South Korea. It’s the shortest of the three coastlines and the least visible to the outside world.
The main port is Nampo, which serves as the maritime outlet for Pyongyang roughly 50 km inland. Nampo sits behind the West Sea Barrage, an 8-kilometer dam-and-lock system completed in 1986 that separates the Taedong River estuary from the sea. The coast here is heavily indented and dotted with islands, and the tidal range is extreme — among the largest in the world, with water retreating across kilometers of mudflat at low tide.
This stretch of coast is also where the Yellow Sea’s geopolitics get sharpest, because North Korea and South Korea have never agreed on where their maritime boundary actually runs (more on that below).
South Korea
South Korea fronts the eastern edge of the Yellow Sea — which Koreans simply call the West Sea, since it’s the sea on their western side. Its coastline is a maze of islands, tidal flats, and reclaimed land.
The standout port is Incheon, the gateway to Seoul and the site of the 1950 amphibious landing that turned the Korean War. Incheon Airport, built on reclaimed land between two islands in the Yellow Sea, is one of the busiest in Asia. The port itself uses massive tidal lock gates to cope with a tidal range that can exceed 9 meters — boats would be left sitting on mud otherwise.
South Korea’s Yellow Sea coast is also home to the Getbol tidal flats, a network of mudflats inscribed as a UNESCO World Heritage Site in 2021 for their biodiversity and role as a stopover for migratory shorebirds on the East Asian–Australasian Flyway. These flats are exactly the kind of ecosystem the sea’s shallow, sediment-rich water produces.
Where the Borders Get Complicated
Three countries sharing one shallow sea means three sets of overlapping claims. This is the part most reference pages skip.
The North–South line. After the Korean War, the UN Command unilaterally drew the Northern Limit Line (NLL) as a de facto maritime boundary in the Yellow Sea. North Korea has never recognized it. The clusters of South Korean–held islands sitting just south of the line — Yeonpyeong and Baengnyeong among them — have been flashpoints for deadly clashes, including the 2010 shelling of Yeonpyeong Island. It remains one of the most militarized stretches of water in the world.
The China–Korea overlap. The Yellow Sea is too narrow for China and South Korea to each claim a full 200-nautical-mile exclusive economic zone (EEZ) without overlapping. Because their entitlements collide, the two countries set up a Provisional Measures Zone — a shared fishing area governed by a bilateral agreement rather than a hard border. Chinese and Korean coast guards still tangle here regularly over illegal fishing, and a long-running dispute centers on Socotra Rock (Ieodo / Suyan Rock), a submerged reef both sides claim within their EEZ.
The takeaway: on a map the Yellow Sea looks like a tidy basin shared by three neighbors. On the water, almost none of the lines are settled.
Yellow Sea vs. Bohai Sea vs. East China Sea
These three get mixed up constantly because they flow into one another. Here’s the clean version:
| Sea | Where it is | Relationship |
|---|---|---|
| Bohai Sea | The northwestern pocket, nearly enclosed by China | An inlet of the Yellow Sea; sometimes counted as part of it |
| Yellow Sea | Between mainland China and the Korean Peninsula | The main body; borders China, North Korea, South Korea |
| East China Sea | South of the Yellow Sea, past the line from the Yangtze mouth to Jeju Island | A separate, deeper sea that borders China, Taiwan, Japan, and South Korea |
The usual dividing line between the Yellow Sea and the East China Sea runs from the mouth of the Yangtze River across to the south side of Jeju Island. South of that, you’re in the East China Sea. The Bohai Sea, by contrast, is so enclosed by Chinese territory that it’s often treated as China’s internal water rather than a shared sea at all.
Frequently Asked Questions
How many countries border the Yellow Sea? Three: China, North Korea, and South Korea.
Why is it called the Yellow Sea? Rivers — chiefly the Yellow River — pour enormous amounts of fine yellow silt into it. After heavy rain or seasonal flooding, the suspended sediment can tint the water a golden-brown, especially near the coast and river mouths.
What’s the difference between the Yellow Sea and the West Sea? They’re the same body of water. “Yellow Sea” is the international and Chinese name (Huang Hai); “West Sea” (Seohae) is what Koreans call it, since it lies to the west of the Korean Peninsula.
How deep is the Yellow Sea? Shallow. The average depth is about 44 meters and the maximum is around 152 meters, which makes it one of the largest shallow seas in the world.
Is the Bohai Sea part of the Yellow Sea? Often, yes. The Bohai Sea is a nearly landlocked gulf in the northwest that opens into the Yellow Sea, and many sources treat it as a sub-basin of it. Strictly, though, it’s usually named separately.
Which countries have the biggest ports on the Yellow Sea? China dominates by volume, with Qingdao, Dalian, and Lianyungang. South Korea’s Incheon is the other major port, serving the Seoul metropolitan area. North Korea’s main port is Nampo, the maritime outlet for Pyongyang.
