Why the World's Largest Church Is in Seoul — Korean Protestantism and the Megachurch

On their first night in Korea, a lot of visitors look out the window and ask, “How many red crosses are there, exactly?” The next question is usually this: why is the world’s largest church in Seoul? Wasn’t Korea a Buddhist country?

Both are half right and half wrong. This article explains Korean Protestantism as a social phenomenon. It doesn’t try to convert you, and it doesn’t tear it down. It just shows where the numbers come from — and whether they’re government statistics or a denomination’s own count.

Is the world's largest church really in Seoul?

Yes — at least by the “single congregation” standard, that’s how it has been described. Yoido Full Gospel Church began in 1958, when pastors Cho Yong-gi and Choi Ja-sil started a church in a tent in Daejo-dong, Eunpyeong-gu, in western Seoul. The founding congregation was five people.

The growth curve is almost unreal. 1,000 members in 1961, 8,000 in 1968, 50,000 in 1977, 100,000 in 1979. Even after moving to Yeouido in 1973, the pace never slowed, and by 1993 it entered the Guinness World Records as the “world’s largest single church” with 700,000 registered members. Some counts put it as high as 830,000 around 2007.

It’s different now. A policy of splitting off branch churches divided the Seoul congregation into several independent churches, and the broader decline in religious affiliation compounded it. The Seoul main church’s registered membership is now reported in the 400,000 range. Still among the largest in the world, but not what it was at its peak.

It sits right next to the National Assembly in Yeouido, toward the Yeouinaru side, so it’s easy to find. Walk through the area on a Sunday morning and you’ll understand immediately.

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Why did Korean Protestantism grow so fast?

There’s no single explanation. It’s usually broken into four layers.

And one more. dawn prayer is the signature practice of Korean Protestantism. Major churches still hold services in the 5–6 a.m. window on weekdays. Yoido Full Gospel Church runs two dawn services, at 5:30 and 6:30 a.m., Monday through Friday. The sight of a parent with a child preparing for exams coming out every dawn for 100 days is not unusual in Korean society.

So what kind of religious country is Korea now?

The most reliable measure is Statistics Korea’s Population and Housing Census. The religion item isn’t surveyed every year — it appears on a 10-year cycle. The most recent published results are the 2015 sample figures.

Table 1. Religious population change, Statistics Korea census (2005 → 2015)

Two things matter. First, in the 2015 survey Protestantism overtook Buddhism for the first time to become the country’s largest religion. Second, even so, the largest group is people with no religion (56.1%). The religious population shrank by nearly 3 million over the decade. Protestantism was the only one to edge up slightly — and the common reading is that this reflects other religions’ much steeper declines rather than Protestant growth.

The 2025 Population and Housing Census also included a religion item, surveyed in October 2025. As of publication, the religion results have not yet been released.

The gaps between government surveys are filled by private ones. Hankook Research’s 2025 religion survey found 51% no religion, 20% Protestant, 16% Buddhist, and 11% Catholic. The methodology differs, so it can’t be compared directly with the census, but the direction is the same. What stands out is that 72% of 18–29-year-olds and 64% of people in their 30s said they had no religion.

What are those red crosses at night?

They’re the thing foreigners ask about most in photos of Seoul’s night skyline. The reason is less theology than real estate and sign regulations.

As urban migration exploded in the 1970s–80s, new churches appeared in huge numbers. Most couldn’t afford their own building, so they rented the second floor or basement of a commercial building. You couldn’t see them from the street. So they put a cross on the roof and lit it with neon — visible at night, visible from far away. Red, which stands out best against the city’s night lighting, became the convention and stuck.

Now they’ve switched to LED, and more areas turn them off late at night over light-pollution complaints. But from Namsan or a bridge over the Han River, hundreds are still lit. Think of them as a visual record of how fast, and in what way, Korean Protestantism seeped into the city.

Where are Seoul’s major megachurches?

A “megachurch” is usually defined as 2,000 or more in Sunday attendance. There are dozens in Seoul and the surrounding area. Below are representative examples chosen for size, recognition, and accessibility to foreigners.

Table 2. Major Seoul megachurches compared

Myungsung Church was founded in 1980 by Rev. Kim Sam-hwan, and as of 2008 it reported 45,000 attending out of 95,000 on the rolls. By size alone it’s among the largest Presbyterian churches in the country.

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What does Seoul look like on a Sunday morning?

Between 8 and 11 a.m. on Sundays, the roads around megachurches are as jammed as a weekday commute. A few things stand out.

Church shuttle buses. Every church runs dozens of free shuttles looping through subway stations and apartment complexes. The church’s name is painted large on the side, so they’re easy to spot. They’re the physical infrastructure that lets a megachurch draw members from beyond its own district.

Multiple service times. One seating can’t hold everyone, so they split the hours. Yoido Full Gospel Church holds five Sunday main-hall services — 7 a.m., 9 a.m., 11 a.m., 1 p.m., and 2:30 p.m. The crowd surge as one service empties and the next files in is genuinely impressive.

Families in suits. The restaurants near a church filling up after the service is a distinctly Sunday scene. If restaurants in Gangnam, Seocho, or Yeouido are unusually busy at Sunday lunch, this is usually why.

How many missionaries does Korea send abroad?

One hallmark of Korean Protestantism is the scale of its overseas missionary force. Relative to population, it’s ranked among the very top in the world.

These are from the “2024 Korean Missions Status” published by the Korea Research Institute for Mission (kriM) together with the Korea World Missions Association (KWMA). Add 516 short-term missionaries with mission organizations and 986 foreign-national missionaries sent by Korean organizations. The total is down slightly from the previous year.

The striking part is aging. Missionaries in their 20s–40s keep shrinking, and those under 30 are a tiny minority. The report warned of a leadership vacuum within a decade. Meanwhile, short-term mission participants (under one year) rose to 7,292, of whom 87.2% are under 30.

These figures are not government statistics but a mission coalition’s own count. Counting standards (long-term vs. short-term, whether families are included) differ by organization, so expect wide variance in international comparisons.

Is there a critical side to this story?

Yes — and it’s a fairly big topic in Korean society. Knowing it helps you follow local conversations as a traveler.

Another recurring issue is hereditary succession of the senior pastorate. The representative case is Myungsung Church. In 2017, when founder Rev. Kim Sam-hwan’s son, Rev. Kim Ha-na, was called as senior pastor, it sparked a controversy over violating denominational law. The first trial found the call violated the anti-succession rule, but the appeals court accepted the denomination’s interpretation that “the restriction no longer applies once five years have passed since the predecessor’s retirement,” and the Supreme Court affirmed it.

Legally it’s settled, but the social debate isn’t over. A defining feature of Korean Protestant discourse is that megachurch finances, real estate, and leadership succession are discussed in a framework resembling corporate governance. That Protestantism became the country’s largest religion while public trust sits low — both are true at the same time.

Can foreigners attend services?

Yes. If anything, you’ll be welcomed, and no reservation or registration is needed. Plenty of people visit as a cultural experience regardless of faith.

Yoido Full Gospel Church English service — Sundays at 9 a.m. and 11 a.m., on the 11th floor of the Second Education Building. A Friday evening service at 8:30 p.m. is held in the same place. The church also runs services in Chinese, Japanese, Indonesian, Vietnamese, Russian, and Spanish.

Onnuri Church Seobinggo campus English service — Sundays at 11:30 a.m. (gymnasium, basement of the Youth Center) and 4 p.m. (praise hall, 5th floor of the Mission Building). English-speaking foreigners, overseas Koreans, and Koreans who want an English service gather together. The church also runs services in more than 10 languages, including Nepali, Mongolian, and Arabic — much of it ministry to migrant workers centered on the M Center in Ansan.

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How is this different from Myeongdong Cathedral or Jogyesa?

Compared with the two places that appear in most guidebooks, the difference in character is clear.

Myeongdong Cathedral (Catholic) — The Gothic building itself, completed in 1898, is a tourist draw. You can look around the interior and courtyard outside Mass times, and there’s an English Mass on Sundays at 9 a.m. It also gained political-historical symbolism as a refuge for protesters during the democratization movement of the 1970s–80s.

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Jogyesa (Buddhist) — The head temple of the Jogye Order, Korea’s largest Buddhist denomination. It sits in the middle of downtown and has an open courtyard, so anyone can walk in. Its templestay programs are well organized, giving foreigners a broad entry point.

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Protestant megachurches — The buildings are mostly modern concrete, so the architectural appeal is limited. What’s worth seeing isn’t the building but the scale and the operation: a main hall seating thousands, multiple service times, shuttle buses, and real-time multilingual interpretation. Approach it as a case study in the organizational capacity Korean society built in a single generation, and it becomes far more interesting.

All three are, before being tourist sites, places of actual worship. Just remember that during services, Mass, and ceremonies, the people who came there take priority.

In short

Korean Protestantism grew to nearly 10 million adherents in about 130 years, and the most dramatic product of that compressed growth is the megachurch on Yeouido. At the same time, the religious population is now shrinking, the exodus of younger generations is unmistakable, and public trust has settled below 20%. Seoul’s red crosses hold both stories at once — a trace of growth, and the infrastructure left behind after growth stopped.