Seoul CBD Office Vacancy Hits Decade High

Seoul's central business district recorded a prime office vacancy rate of 8.2% in Q1 2026, marking the highest level in over a decade and representing a sharp increase from the 5.1% registered in the same period last year. The 310-basis-point jump reflects a convergence of new supply completions and tenant relocations to newer developments in the Gangnam and Yeouido submarkets, where landlords have been offering more competitive lease packages. Industry analysts expect the vacancy rate to breach 9% by the end of the year as an additional 1.2 million square feet of Grade A office space is scheduled for completion in the second half of 2026.

  • CBD vacancy rate (Q1 2026): 8.2%
  • CBD vacancy rate (Q1 2025): 5.1%
  • Change YoY: +310 bps
  • New supply pipeline (H2 2026): 1.2 million sq ft
  • Average Grade A rent (CBD): KRW 32,400/pyeong/month

Market Context

The rise in vacancy marks a turning point for Seoul's office market, which had enjoyed several years of tightening conditions following the post-pandemic flight to quality. Between 2022 and 2024, CBD vacancy rates hovered between 3.5% and 5.5%, buoyed by strong demand from technology firms and financial institutions expanding their Korean operations. That demand has not disappeared, but it has shifted geographically. Several major tenants, including a global consulting firm and two domestic fintech companies, relocated from older CBD towers to newly completed buildings in the Gangnam Business District during Q4 2025 and Q1 2026, according to data from Cushman & Wakefield.

Average Grade A rents in the CBD have softened modestly to approximately KRW 32,400 per pyeong per month, down 2.8% from the peak of KRW 33,330 recorded in mid-2025. By contrast, Gangnam Grade A rents have firmed to KRW 35,100 per pyeong per month, widening the premium over the CBD to roughly 8.3%. Yeouido has also attracted tenants seeking newer specifications, with its vacancy rate declining to 4.6% from 6.1% a year earlier. The divergence underscores a clear flight-to-quality trend that is penalising older CBD stock while rewarding districts with modern, ESG-compliant buildings.

Supply Pipeline Adds Pressure

The supply side offers little relief for CBD landlords in the near term. Two major tower completions — a 48-storey mixed-use development near Gwanghwamun and a 35-storey office tower adjacent to Seoul Station — are expected to deliver a combined 820,000 square feet of lettable area by Q4 2026. Pre-leasing across both projects stands at roughly 40%, well below the 65% threshold that brokers typically consider healthy for a building approaching completion. Landlords of existing CBD stock have begun responding with rent-free periods of up to four months and enhanced fit-out contributions, measures that were virtually absent during the tight market conditions of 2023.

Savills Korea estimates that effective rents, once incentives are factored in, have already fallen by as much as 6% from their 2025 peak in secondary-grade CBD buildings. Older towers with limited column-free floor plates and weaker sustainability credentials are bearing the brunt of tenant departures. Several owners are now exploring asset repositioning strategies, including partial conversions to co-working or medical office use, to stem occupancy losses.

What This Means for Investors

For institutional investors, the widening vacancy gap between Seoul's CBD and its competing submarkets presents both risk and opportunity. Cap rates for prime CBD assets have edged up to the 4.0–4.3% range, compared with sub-3.8% in Gangnam, making select CBD buildings more attractive on a yield basis for buyers willing to underwrite a repositioning or lease-up strategy. However, the volume of incoming supply suggests that rental recovery in the CBD is unlikely before late 2027 at the earliest. Investors with shorter hold periods should exercise caution, while value-add funds may find the current cycle an opportune entry point — provided they budget adequately for capital expenditure on building upgrades to meet evolving tenant requirements around energy efficiency and flexible floor configurations.