If we take the resort cluster on the west coast of Okinawa’s main island and cut it as a 10 km radius centered on Seragaki in Onna Village (恩納村), there are 34 lodging properties with 30 or more rooms, totaling 6,819 rooms. Overlaying those 6,819 rooms on the tsunami inundation assumption (maximum-class tsunami) that Okinawa Prefecture set in March 2015, using each property’s representative point, 12 properties and 2,762 rooms — 40.5% on a room basis — fall inside the assumed inundation zone. However, 1,660 of those rooms (60% of the in-zone total) are in the band with an inundation depth of less than 1 m, while the 2 m-plus bands account for only 4 properties and 457 rooms. Meanwhile, Onna Village’s estimated settled ADR stood at ¥21,895 in September 2026, up 9.2% year on year, and new openings and rebrands continue on the west coast — in July, the 139-room BLISSTIA SUITES & RESORT Okinawa Onna opened. This article first maps and tabulates the room distribution by inundation-depth band, then estimates per-room BCP investment in equipment placement — relocating power receiving/transforming equipment to upper floors and installing emergency generators — and converts it, using Onna Village’s estimated settled ADR, into payback sensitivities that can be used directly in insurance and lending reviews.

Summary — Decide Equipment Placement by Depth Band, Not by “In Zone or Not”

To state the conclusions first: First, the fact that about 40% of west-coast resort rooms lie inside the tsunami inundation zone is not a verdict on location quality; it is a precondition that comes with any oceanfront asset. Being on the beach is the source of the room rate, and many of the 4,057 rooms outside the zone are excluded only because of terrain — they sit on the tip of a headland or atop a terrace. Second, because 60% of in-zone rooms are concentrated in the band under 1 m, many properties can reach a functional-continuity level using the approach at the core of the MLIT/METI guideline: “place electrical equipment at a sufficient height relative to the assumed inundation depth.” Third, the capex involved fits within a business plan. Our estimate for retrofitting the 12 in-zone properties is ¥98K–280K per room, equivalent to 6–16 days of room revenue at Onna Village’s estimated settled ADR. Below, we review the published figures, our methodology, the distribution by depth band, demand and land prices, equipment capex, and insurance and lending, in that order.

Okinawa’s Tsunami Inundation Assumption — Maximum Class Set in March 2015; Warning Zones Designated for 39 Municipalities in 2018

We begin with the published baseline. Under Article 8 of the Act on Regional Development for Tsunami Disaster Prevention, Okinawa Prefecture set and published the “Okinawa Prefecture Tsunami Inundation Assumption” in March 2015. The assumption shows “the area (inundation area) and depth (inundation depth) of flooding assumed when a maximum-class tsunami occurs under adverse conditions,” and the prefecture notes that it “is intended to advance tsunami-resilient community development centered on evacuation, and does not indicate the extent of tsunami disasters or damage.” Because the calculation uses a 10 m mesh, narrow openings in seawalls and small rivers are not fully represented, and the prefecture also states explicitly that flooding may occur outside the zone depending on terrain and structures. The tsunami inundation layer in the MLIT Real Estate Information Library used in this article incorporates this prefectural assumption as National Land Numerical Information (FY2016 edition), with inundation depth provided in six classes: 0.01–0.3 m, 0.3–1 m, 1–2 m, 2–5 m, 5–10 m and 10–20 m.

Next is zone designation. Under Article 53 of the same Act, the prefecture designated tsunami disaster warning zones for 39 municipalities — all except Haebaru Town and Yonaguni Town — on March 27, 2018; Nago City, Onna Village, Yomitan Village and Uruma City were all designated on that date. Warning zones are for establishing evacuation systems and do not restrict construction or development. The prefecture states clearly that “there are currently no designated areas in Okinawa Prefecture” for tsunami disaster special warning zones, which do carry certain building restrictions. The reference water level published alongside warning zones is “a water level determined by adding to the assumed inundation depth a value deemed necessary considering the rise in tsunami water level caused by impact with buildings, etc.,” and serves in practice as the benchmark for deciding which floor to place equipment on.

Scope and Method — 34 Properties and 6,819 Rooms within 10 km, Judged at Each Property’s Representative Point

The scope is lodging properties with 30 or more rooms confirmed as on sale in September 2026 within a 10 km radius centered near Seragaki, Onna Village (26.50°N, 127.86°E). The area runs from the borders with Yomitan Village and Ishikawa in Uruma City in the south to Koki and Busena Cape in Nago City in the north, covering nearly all of the main west-coast beachfronts — Manza, Tancha, Maekaneku, Seragaki, Nakama, Kise and Koki. MetroEngines Research’s property data returned 35 matches, but one property in Koki, Nago City was registered at the same coordinates under both its pre- and post-rename names; after confirming from official information that it is the same building, we counted it as one property. The result is 34 properties and 6,819 rooms.

Inundation depth was determined by mechanically checking whether each property’s representative point (latitude/longitude) falls within the tsunami inundation polygons in the Real Estate Information Library (132 tiles at zoom level 14, 9,248 polygons); where a point touched multiple bands, the deeper band was used. A representative point is just one point somewhere on the building and does not reflect elevation differences within the site or the building footprint. “In zone” in this article therefore should not be read as meaning the entire property would flood, but as “a property for which inundation depth should be set as a precondition when planning equipment placement and evacuation.” For price-tier classification we used grade categories based on the listed prices aggregated by MetroEngines Research for September 2026 (2 guests per room, tax-inclusive): 8 luxury, 11 upper-midscale, 9 midscale, 4 economy, 1 budget, and 1 with no price data.

Results by Depth Band — 2,762 Rooms (40.5%) In Zone, 1,660 of Them in Bands Under 1 m

Results are shown in Table 1 and Figure 1. Of the 6,819 rooms, 12 properties and 2,762 rooms are inside the assumed zone — 40.5% on a room basis. By band, the 0.3–1 m band is the thickest at 4 properties and 1,380 rooms, comprising the large 826-room property at Tancha Bay and three properties in Seragaki. In Seragaki, Hyatt Regency Seragaki Island Okinawa (343 rooms), opened by Hyatt Hotels Japan in August 2018, sits in the same band; it was designed with low-rise wings distributed across an island-shaped site. The 1–2 m band has 3 properties and 645 rooms, centered on two mid- to high-rise properties facing the beaches at Sun Marina and Fuchaku. The 2 m-plus bands comprise 4 properties and 457 rooms in Koki and Kise, Nago City — only 16.5% of in-zone rooms.

The key to reading this distribution is that west-coast resorts share a design that “faces the sea.” Many of the 4,057 out-of-zone rooms sit atop the Manza and Busena headlands or on the edge of terraces descending seaward from National Route 58; they fall outside the zone because of ground elevation, not distance from the sea. Conversely, in-zone properties sell their direct continuity with the sand — guests can walk straight down to the beach — so a shallow depth band is, in effect, a measure of “closeness to the beach.” That is precisely why this article does not use “in zone or not” as a location-evaluation axis, and instead moves on to the design and operational question of which equipment to place where in each depth band.

On the Map — Shallow Bands from Tancha to Seragaki, Deep Bands from Koki to Kise

Figure 2 overlays the tsunami inundation depths, aggregated to an approximately 100 m mesh, on a map and shows the 34 properties as circles sized by room count. The circle outline color indicates the depth band at each property’s representative point; out-of-zone properties are shown in gray. In Tancha, Maekaneku and Fuchaku in southern Onna, the assumed inundation stays within a narrow strip along the coast, and most properties fall in the 0.3–1 m or 1–2 m bands or outside the zone. From Seragaki to Nakama, low, flat reclaimed land and sandbars continue, so even island-shaped sites fall into the 0.3–1 m band. In contrast, at Koki and Kise facing Nago Bay, the 2–5 m band extends close to the shoreline, catching properties built between the national highway and the coast. Even within the same 10 km radius, this terrain difference — inundation depth deepening toward the back of the bay — separates the priorities for equipment placement.

Demand and Rates — Onna’s Estimated Settled ADR ¥21,895 in September (+9.2%), ¥33,000 in August

To think about recovering equipment capex, we need to establish how much room revenue this cluster generates. Lining up MetroEngines Research’s estimated settled ADR (municipal medians) for September 2026, Onna Village was ¥21,895 (N=44), up 9.2% from ¥20,046 a year earlier. Yomitan Village was ¥22,553 (N=9), slightly above Onna, but on a small sample of 9 properties. Nakijin Village in the north stands out at ¥40,438, with small villa-type properties pushing up the median. Nago City was ¥11,384 (N=25); because it includes downtown business hotels, it comes out below west-coast resort levels. The median for Okinawa’s resort category was ¥16,799 (N=282, +7.3% YoY), and ¥12,040 for the prefecture overall (N=515, +10.0%).

Seasonality is shown in Figure 4: Onna Village’s estimated settled ADR peaks in summer at ¥30,375 in July 2026 and ¥32,961 in August, and runs at ¥17,000–21,000 from January to June. Compared with 2025, every month from April 2026 onward exceeded the prior year, with the August summer peak up 16.3%. The 12-month average from October 2025 to September 2026 is ¥21,562, which this article uses as the annual ADR in its payback estimates. On occupancy, MetroEngines Research estimates Okinawa’s resort category at 87.2% in August 2026 (184 properties, 16,683 rooms) and 87.7% in September (182 properties, 16,530 rooms). Among listed REIT disclosures, Japan Hotel REIT Investment Corporation (8985) reported regional results for its 29 hotels with variable rent, showing Okinawa (4 hotels) in August 2026 at 82.5% occupancy, ADR ¥47,112 and RevPAR ¥38,853. The REIT owns Oriental Hotel Okinawa Resort & Spa (オリエンタルホテル 沖縄リゾート＆スパ; 361 rooms, acquisition price ¥14,950 million) in Nago City within this area, which by our judgment lies outside the assumed zone. Taking these into account, our estimates conservatively set annual occupancy at 80%.

Land Prices and Zoning — Onna Commercial Land +11.0%; No Zoning Designation on the Coast

Location value also shows up in land prices. In the 2026 (Reiwa 8) land price survey published by Okinawa Prefecture on September 16, 2026 (as of July 1, 2026), the prefecture-wide all-use average rose 5.8% (prior year +6.1%), extending its rise to 13 consecutive years while narrowing the pace. Onna Village outpaced the prefectural average, with residential land up 8.5% (prior year +10.7%), third in the prefecture, and commercial land up 11.0% (prior year +7.8%), tied for third. By benchmark site, Onna (Pref.) -1 (Aza Maeda) rose 14.4% from ¥37,500/㎡ to ¥42,900/㎡, the fourth-highest residential increase in the prefecture, and Nago (Pref.) -3 (Aza Yohena) placed third at +14.8%. Including Chatan Town (residential +11.7%, commercial +11.8%) and Ginoza Village (+11.0%, +11.5%), west-coast tourism locations occupy the top of the prefectural rankings. The prefecture cites as background that “domestic tourist numbers hit a record high in FY2025” and foreign tourist numbers “have broadly reached pre-COVID levels,” while attributing the narrower rise to soaring construction costs, rising prices and interest rates, and labor constraints.

On zoning, checking the locations of the 34 properties against the zoning layer in the Real Estate Information Library, only one property, on the Ishikawa side of Uruma City, lies within a designated zone; no zoning designation could be confirmed at the property locations on Onna’s coast or in Koki and Kise in Nago City. Because uniform restrictions on building use and floor-area ratio under zoning do not apply, there is relatively high design freedom when reconfiguring which floors house equipment or re-drawing flood-defense lines through extensions. In exchange, the reference water level of the tsunami disaster warning zone, the prefectural landscape ordinance, and consultations on height and green space as a resort area become the practical conditions. Precisely because land prices keep rising and zoning constraints are loose, the decision about what to keep in the seaward low-rise sections and what to move upstairs ties directly to asset value.

BCP Equipment for Existing Hotels — Upper-Floor Power Equipment and Emergency Generators at ¥98K–280K per Room

The guideline for equipment placement is the “Guidelines for Flood Countermeasures for Electrical Equipment in Buildings,” compiled by MLIT and METI in June 2020. The guidelines call for each building to set an “assumed inundation scale (assumed inundation depth and assumed inundation duration)” and a “target level” of countermeasures needed for functional continuity, then present countermeasures in three groups. The first is “installing electrical equipment in locations with low inundation risk,” positioned as follows: “if installed at a position of sufficient height in light of the assumed inundation depth, a relatively reliable effect can be expected regardless of how the response unfolds during a flood.” Yet for existing buildings the guidelines also note that “for existing buildings with major spatial constraints, implementation can be difficult.” The second is setting a flood-defense line, applying flood barriers and watertight doors at entrances, opening measures for dry areas and ventilation openings, and drainage backflow prevention continuously along the line. The third is early-recovery measures and a timeline in case the assumption is exceeded. The guidelines mainly cover river flooding, inland flooding and storm surge, but the case collection includes a government-building plan premised on tsunami inundation depth, so the approach can be applied to tsunamis as well.

Applying this framework to the depth bands reveals where the response should focus (Table 4). In the 0.01–0.3 m and 0.3–1 m bands (5 properties, 1,660 rooms), setting the flood-defense line at about 1 m above the ground-floor level and placing power receiving/transforming equipment, distribution panels and emergency generators on the 2nd floor or above, or on raised platforms, brings electrical equipment to a functional-continuity level. Ground-floor kitchens and laundries are hard to relocate, so the realistic approach is to keep them within the flood-defense line using flood barriers and watertight doors, designate an upper-floor banquet pantry as a backup kitchen, and switch linen via outsourcing contracts. In the 1–2 m band (3 properties, 645 rooms), receiving/transforming equipment and generators are moved upstairs on the assumption that the entire ground floor floods, with kitchens and laundries treated as early-recovery items. In the 2 m-plus bands (4 properties, 457 rooms), the baseline is to designate the building’s upper floors as a tsunami evacuation building, secure evacuation space two floors above the floor corresponding to the reference water level, and place electrical equipment on that floor or higher. That mid- to high-rise resorts can serve as vertical-evacuation shelters for the community is also a role these properties hold.

So how much does it cost? Using published market prices for equipment, we estimated by size band the cost of relocating receiving/transforming equipment upstairs and newly installing emergency generators at existing hotels (Tables 5 and 6). For cubicle-type high-voltage receiving/transforming equipment, market prices shown by an energy-efficiency subsidy information site as of September 2026 are ¥2–6 million including installation for 50–300 kVA, and ¥10–20 million or more for 300 kVA and above. Upstairs relocation in an existing building adds structural reinforcement, cable extension, hoisting, removal of existing equipment and outage work, so as an editorial assumption we applied a factor of 1.5–2.5x. For emergency generators, we used market prices (as of December 2025) of ¥5–8 million for a 60–100 kVA diesel unit, ¥8–15 million for 100–200 kVA, and ¥3.3–10 million for outdoor installation work. Note that resorts require large capacity because of pools, large baths and large kitchens, and properties with 200 or more rooms may exceed the upper end.

The estimate puts the per-room cost at ¥166K–485K for properties up to 99 rooms, ¥213K–607K for 100–199 rooms, and ¥78K–221K for 200+ rooms. The five 200-plus-room properties, which hold 74% of in-zone rooms, carry the lightest per-room burden because generator and receiving/transforming costs are spread across many rooms. Assuming all 12 properties take the same measures, the total is ¥271M–774M, or ¥98K–280K per room, with a midpoint of ¥189K. Emergency power carries extra weight in Okinawa because long outages from typhoons — not just tsunamis — are an annual given. During Typhoon No. 6 in August 2023, the slow-moving storm prolonged outages, and evacuation shelters in 11 municipalities across the prefecture lost power, with reports of shelters running electric fans on emergency power. That a generator can be depreciated not as tsunami equipment but as equipment that keeps the hotel operating through every summer’s typhoons is what sets the west-coast estimate apart from Kushiro or Shirahama. The point that legally required emergency power covers only 30–60 minutes for fire response, leaving the power needed for 72 hours of continued operation to discretionary investment — and the cost of that — is covered across 16 markets nationwide in Hotel Backup Power in Japan: 72-Hour Upgrade Costs ¥109K–142K a Room.

Payback Sensitivity — Midpoint ¥189K Equals 11 Days of Room Revenue; ¥65 ADR Uplift Recovers It in 10 Years

How should the midpoint add-on of ¥189K per room be weighed against Onna Village’s estimated settled ADR? Multiplying the 12-month average ADR of ¥21,562 by 80% annual occupancy gives room revenue of ¥17,250 per room per day, or ¥6.3 million per year. The midpoint ¥189K equals 11.0 days of room revenue; the low end of ¥98K equals 5.7 days and even the high end of ¥280K equals 16.2 days. If equipment floods and recovery takes a month, the lost room revenue is ¥520K per room — roughly the same scale as the high-end add-on. In other words, avoiding a single extended closure would pay back the investment, and viewing it together with the design of property-insurance deductibles and business-interruption cover makes the role of the add-on clear.

It can also be seen from the rate side. The annual ADR uplift needed to recover the midpoint ¥189K over 10 years is just ¥65 per night at 80% occupancy. Table 8 shows payback years as uplift and occupancy vary: an uplift of ¥100 at 80% occupancy pays back in 6.5 years, and ¥200 in 3.2 years. Given that Onna Village’s estimated settled ADR moved +9.2% YoY (about ¥1,850) in September 2026, a ¥65–100 uplift falls within the margin of error of pricing. In a review, presenting three points — “the property is in the band under 1 m; receiving/transforming equipment and generators are on the 2nd floor or above; the cost equals 11 days of room revenue, or ¥65 in ADR terms” — allows the revenue impact of equipment placement to be explained quantitatively.

200-Room New-Build Model — BCP Add-On Is 0.4–1.0% of Construction Cost; Rate Tier Determines Yield

What about rebuilds or new development? Assuming a 200-room upper-midscale property with 35 ㎡ rooms and a 60% guestroom-area ratio, gross floor area is about 11,667 ㎡ (3,529 tsubo). Using the 2025 actual of ¥2.026 million per tsubo for RC construction based on MLIT’s Building Construction Statistics, construction cost is ¥7.15 billion (¥35.75 million per room); factoring in the Japan construction cost escalation shown by Turner & Townsend in March 2026 (+5.3% in 2026, +5.0% in 2027) brings it to ¥7.91 billion. For land, we set ¥860 million as a reference value by applying the 2026 land price survey’s Onna (Pref.) -1 (Aza Maeda, residential) value of ¥42,900/㎡ to 20,000 ㎡. Transactions in coastal resort land are scarce, so this figure is only a rough gauge. The BCP add-on, on the same assumptions as the 200+ room band in Table 5, is ¥26–75 million with a midpoint of ¥51 million — just 0.4–1.0% of construction cost. For GOP margin, considering segment benchmarks (20–40% for resort hotels) and the 38.9% actual for 91 MHM-operated properties disclosed by Invincible Investment Corporation (December 2024 period), we adopted 30% as a conservative first-year value.

There are two takeaways from the estimate. The first is how little the BCP add-on moves yield. In Scenario A, 4.72% without the add-on becomes 4.69% with the midpoint add-on — a drop of just 0.03 point. Compared with construction cost inflation lowering yield by 0.4 point in the same scenario, the equipment placement decision is not a constraint on investment returns but a precondition that can be settled at the earliest design stage. The second is that what moves yield is the choice of rate tier: Scenario A at the Onna average yields 4.69%, B in the upper resort tier 6.52%, and C in the top tier 9.78% — roughly 2 points of yield for every ¥10,000 change in ADR. On the west coast, upper-tier supply continues to refresh: in July 2026 the 139-room BLISSTIA SUITES & RESORT Okinawa Onna opened as a hotel-condominium, and The Ritz-Carlton, Okinawa reopened the same month after renovation. What a new entrant should focus on narrows to a single point: having settled the depth-band response as a precondition, which rate tier to build in.

Insurance and Lending — Tsunami Falls Under Earthquake Cover; Reviews Ask About Depth and Equipment Floors

Start with insurance. In the commercial fire insurance that hotels carry, damage from earthquakes, eruptions and tsunamis is generally excluded from basic coverage, and is typically covered separately through commercial earthquake insurance or riders covering earthquake, eruption and tsunami. The flood-rate segmentation being discussed for residential policies (from October 2024, five tiers by municipality, with a rate difference of about 1.2x on reference pure premium rates) is a mechanism for river and inland flooding; tsunami preparedness belongs to earthquake-related cover. For reference, the basic rates for residential earthquake insurance (Ministry of Finance, policies starting October 2022 or later) per ¥10 million of insured amount per year are ¥11,600 for Class I structures (steel/concrete) and ¥19,500 for Class Ro structures (wood) in Okinawa, versus ¥27,500 and ¥41,100 in Tokyo, ¥23,000 and ¥41,100 in Kochi, and ¥7,300 and ¥11,200 in Hokkaido — placing Okinawa in the middle tier nationally. Rates and limits for commercial policies are set by individual underwriting so these figures do not apply directly, but the inundation depth from the tsunami assumption and the floor on which electrical equipment sits are materials that can be presented as-is when negotiating underwriting terms. How the same hazard difference flows through two channels — insurance premiums and lender LTV — to NOI and yield is broken down across 10 markets nationwide in Hotel Fire Insurance: ¥1.01M Flood-Zone Gap, PML Moves LTV and IRR.

On the lending side, institutional moves to incorporate climate-related physical risk into collateral valuation are advancing. In a March 2026 report, Sumitomo Mitsui Trust Research Institute stated that real estate is “an asset with a fixed location and long useful life, so the impact of physical risks such as flooding on asset value, rental income and collateral value persists over the long term,” noted that empirical studies show “cases where flood risk is not sufficiently reflected in market prices,” and pointed toward incorporating probabilistic indicators — expected inundation depth, exceedance probability and expected loss — into location evaluation. MLIT also published the “Guide to Physical Risk Assessment under the TCFD Recommendations” in March 2023, setting guidance for companies to assess flood risk from a financial perspective. In real estate transactions, explanation of flood risk using flood hazard maps was added to the important-matters disclosure from August 2020, and tsunami disaster warning zones are also subject to disclosure as statutory zones. What reviewers check is not whether a property is in or out of the zone, but three points — “what is the assumed inundation depth,” “on which floor are the receiving/transforming equipment, generators and distribution routes,” and “is there a timeline for resuming operations after flooding” — and the frameworks in Tables 4 and 6 correspond directly to these questions.

Framing the Investment Decision — Three Approaches with Depth Band as the Precondition

To sum up: the figure that about 40% of rooms in Okinawa’s west-coast resort cluster lie inside the tsunami inundation zone sets preconditions for equipment placement and evacuation planning; it does not diminish the value of the location. 60% of in-zone rooms are in bands under 1 m, and the required add-on of ¥98K–280K per room fits within 6–16 days of room revenue at Onna Village’s estimated settled ADR. In a market where land prices are rising faster than the prefectural average and estimated settled ADR is up 9.2% YoY, the cost of putting equipment upstairs is a scale that a ¥65 ADR uplift can absorb within 10 years. This autumn, when budgets for next year’s insurance renewals and equipment upgrades are set, taking stock of equipment investment by depth band in these units is the shortcut to negotiating insurance premiums and loan terms on your own numbers.

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