Prime office vacancy is expected to rise as supply and relocations increase.

Prime Office Vacancy in Seoul CBD Approaches 10-Year High

Prime office vacancy in Seoul's central business district is forecast to breach 8% by end-2025, a threshold not crossed since 2015, as a significant pipeline of new Grade A supply enters the market simultaneously with a wave of tenant relocations. The convergence of these two forces is reshaping rent dynamics across the CBD, Yeouido, and Gangnam submarkets, putting downward pressure on effective rents even as headline asking rates remain nominally stable. Analysts tracking the Seoul office sector warn that the headline vacancy figure understates the true availability rate once shadow space — subleased floors and uncommitted pre-lets — is factored in. For institutional investors holding core Seoul office assets, the shift represents a meaningful change in the risk profile of what has historically been one of Asia-Pacific's most tightly held office markets.

• Projected CBD vacancy rate (end-2025): ~8.0%
• Current prime office vacancy (Q1 2025): ~6.4%
• New Grade A supply entering market (2025): approx. 320,000 sqm GFA
• Average prime net effective rent change (YoY): -3.2%
• Prime office yield range, Seoul CBD: 4.2%–4.8%

What Is Driving the Supply Surge?

Several large-scale developments that were delayed during the post-pandemic construction period are now completing concurrently, flooding the market with new inventory at a moment when occupier demand has plateaued. Key completions include towers in the Gwanghwamun corridor and the Mapo district, both of which are competing aggressively for anchor tenants with incentive packages including extended rent-free periods of up to 12 months and substantial fit-out contributions. This landlord-funded incentive environment is compressing net effective rents well below face rates, a dynamic that does not always appear in headline rent indices but is acutely felt by asset owners managing income returns. The situation is further complicated by the relocation of several major Korean conglomerates and financial institutions to newer, more energy-efficient buildings, leaving second-generation space in older Grade A towers difficult to re-let without significant capital expenditure on refurbishment.

Tenant flight-to-quality is a structural trend accelerating the vacancy problem rather than simply redistributing it. Occupiers are using lease expiries as leverage to upgrade to ESG-compliant buildings with better amenity, lower energy costs, and stronger green credentials — requirements increasingly mandated by corporate sustainability frameworks. Older prime stock, even in prime CBD locations, is struggling to compete on these metrics without landlord investment, and many private owners lack the capital or appetite to undertake the necessary upgrades in a softening rent environment.

How Does This Compare to the Broader Asia-Pacific Office Market?

Seoul's rising vacancy stands in contrast to some other Asia-Pacific markets where office supply has been more restrained. Singapore's CBD Grade A vacancy held at approximately 4.5% through Q1 2025, supported by limited new completions and steady demand from financial services and technology occupiers. Tokyo's central five wards similarly maintained vacancy below 5%, underpinned by a weaker yen attracting foreign occupier interest and a more disciplined development pipeline. Hong Kong remains an outlier in the opposite direction, with CBD vacancy exceeding 14% as structural demand challenges persist, making Seoul's trajectory a concern but not yet a crisis by regional comparison. The Seoul market's relative tightness over the past decade had supported strong capital value growth, with prime CBD assets transacting at yields as low as 3.8% at the 2022 peak; the current softening suggests a repricing cycle is underway that could push yields back toward the 4.5%–5.0% range over the next 12 to 18 months.

What This Means for Buyers and Investors

For investors evaluating Seoul office acquisitions, the rising vacancy cycle creates both risk and selective opportunity. Buyers with long-term hold strategies and the capital to fund tenant incentives and refurbishment may find that motivated sellers — particularly those facing loan maturities in a higher interest rate environment — are willing to transact at discounted entry prices that underwrite acceptable forward yields. The key underwriting variable is lease-up velocity: in a market where incentive packages are extending to 12 months rent-free, investors must stress-test income assumptions over a longer void period than has been typical for Seoul prime assets. Conversely, investors in existing Seoul office assets should scrutinise upcoming lease expiries carefully, particularly for tenants in older stock who may be evaluating relocation to newer completions. Proactive lease restructuring and targeted capital investment in ESG upgrades are likely to be the most effective tools for defending occupancy and income through the current supply cycle. The market is not distressed, but the window of easy returns from passive ownership of Seoul prime office has narrowed considerably.

Frequently Asked Questions

What is the current prime office vacancy rate in Seoul's CBD?

As of Q1 2025, prime office vacancy in Seoul's CBD stands at approximately 6.4%, with forecasts pointing to a rise toward 8.0% by end-2025 as new supply completes and tenants relocate to newer buildings.

How are new office completions affecting rents in Seoul?

New supply is compressing net effective rents by forcing landlords to offer incentive packages including up to 12 months rent-free and fit-out contributions. Average prime net effective rents have declined approximately 3.2% year-on-year as a result, even as headline asking rents remain relatively stable.

How does Seoul's office vacancy compare to other Asia-Pacific markets?

Seoul's rising vacancy contrasts with Singapore (approximately 4.5% CBD vacancy) and Tokyo (below 5%), but remains well below Hong Kong's elevated 14%-plus vacancy rate. Seoul is experiencing a cyclical correction rather than a structural collapse, though the direction of travel warrants investor caution.

What yield can investors expect from Seoul prime office assets?

Prime Seoul CBD office yields currently range between 4.2% and 4.8%, up from a cycle low of approximately 3.8% at the 2022 peak. Further yield expansion toward 4.5%–5.0% is anticipated over the next 12 to 18 months as vacancy rises and income risk increases.

What should office investors in Seoul prioritise right now?

Investors should focus on lease expiry management, proactive tenant retention, and targeted ESG-related capital expenditure to maintain competitiveness against new supply. Buyers entering the market should stress-test underwriting assumptions for extended void periods and factor in landlord incentive costs when modelling forward returns.