By Aidan Sowa · October 2026 · St Simons Island, GeorgiaResidential lots on St Simons Island are worth substantially more than residential lots in Brunswick, and the gap is structural rather than temporary. The island is a barrier island where buildable land is finite, while Brunswick is the neighboring mainland city and Glynn County seat across the causeway, where land supply is far less constrained. On the island, the simplified residual illustration in the research leaves land value near $550,000 to $650,000 from a $1,500,000 new build sale, after roughly $620,000 in hard and soft construction costs and a builder margin near 20 percent, and before $20,000 to $35,000 in site preparation costs (Frontier Capitals, 2026). No comparable residual is documented for Brunswick lots in the source material, and this report does not invent one. What the material does document, repeatedly, is the direction and the reason: island comps are not Brunswick comps, and pricing an island lot from mainland sales understates it.
The island side of the comparison can be stated with figures. New construction on standard island lots has sold in the $1.1M to $1.9M range depending on beach or marsh proximity and lot size (Redfin, 2026). Older island homes changed hands at an average of 23.1 percent of new build prices on comparable lots, so where a new build sells for $1,400,000, the older home changed hands for roughly $325,000, with over three quarters of the finished value sitting in the land (Frontier Capitals, 2026). Builders acquired 9 of the 17 sampled older homes, which means the island lot market is actively cleared by builders paying land driven prices (Frontier Capitals, 2026). Across the causeway, none of those three conditions holds in the same way: finished prices are lower, land is more plentiful, and the buyer pool for a vacant lot is not dominated by builders chasing a scarce island position. Owners weighing how much a residential lot is worth in St Simons Island on its own terms will find the island only calculation there, while this report keeps the cross causeway comparison in view.
A warning belongs at the front of any comparison. Relocation and market comparisons run across the causeway in daily life, because island residents work, shop and attend school in Brunswick and Brunswick residents cross to the island for the beach. Lot value does not travel with them. A price per square foot that is generous in Brunswick can be far below market on the island, and an island owner who accepts a mainland framed offer without checking island residuals leaves the scarcity premium on the table.
Key Findings
- Island new construction on standard lots has sold in the $1.1M to $1.9M range, the finished prices from which island lot residuals are worked (Redfin, 2026).
- The simplified island residual leaves land value near $550,000 to $650,000 from a $1,500,000 new build sale before site preparation (Frontier Capitals, 2026).
- Sampled older island homes averaged 23.1 percent of new build prices, confirming that most finished value sits in island land (Frontier Capitals, 2026).
- The island sample minimum lot was 6,098 sq ft, and flood setbacks constrain the buildable envelope that supports island lot value (Frontier Capitals, 2026).
- No verified Brunswick lot residual is published in the source material, so the comparison is made by method and direction, not by an invented mainland figure (Frontier Capitals, 2026).
Why does scarcity price island lots above mainland lots?
Scarcity prices island lots higher because the island cannot add land. St Simons Island is bounded by ocean, marsh and river, and every buildable parcel already exists inside those boundaries. When demand for finished island homes rises, builders cannot move one street further out. They must compete for the fixed stock of lots, many of them occupied by ranch homes and cottages built from the 1950s through the 1970s. That competition is visible in the sample: a builder demand rate of 52.9 percent, with 9 of 17 older homes acquired by builders (Frontier Capitals, 2026). In Brunswick, by contrast, a builder who finds one lot expensive can look to the next subdivision or the next parcel of mainland ground. The ability to walk away caps what any single mainland lot can command.
Demographic and housing context for the wider area helps frame demand without replacing lot level evidence. Housing characteristics for the Brunswick metropolitan area describe the combined island and mainland market in which both sides of the causeway sit (U.S. Census Bureau, 2025). Broader demographic data for Glynn County provides the population backdrop for that combined market (U.S. Census Bureau, 2025). Those area wide figures explain why people want to live in the county. They do not explain the lot gap, because the gap comes from geography, not from population. Two lots in the same county and the same metro can carry very different values when one sits on a finite island and the other sits on expandable mainland.
Finished price movement on the island itself adds a further layer of context, visible in the sold record for island new construction (Redfin, 2026). Rising finished prices lift island residuals quickly because construction costs and margin do not rise as fast as the finished price in a strong market, leaving more for the land. On the mainland, the same rise is absorbed more easily by new supply. Owners who want to understand how much lot size affects property values in St Simons Island are really asking how this scarcity is divided among lots of different sizes, since a larger island lot captures more of a premium that a larger mainland lot captures only weakly.
How should an island lot be valued without using mainland comps?
An island lot should be valued from island finished sales, worked backward through the residual method, with mainland comps set aside entirely. Start with what a new home on the specific lot can sell for, using island new construction sales in the $1.1M to $1.9M documented range adjusted for beach or marsh proximity and lot size (Redfin, 2026). Subtract hard and soft construction costs and a builder margin near 20 percent. The remainder is the land value, before site preparation of $20,000 to $35,000 (Frontier Capitals, 2026). That is the method the research itself uses, and it produces figures that recorded island deeds can then confirm or correct.
Parcel records are the check on the second half of the method. Lot dimensions and flood zone designations determine the buildable footprint that the finished price assumes (Glynn County Board of Assessors, 2026). A lot whose envelope is cut by setbacks supports a smaller finished home and a lower residual, even if its total area looks generous. Building permit and tree protection requirements also shape what can actually be placed on the lot, since the live oak canopy is protected and priced around (Glynn County Community Development, 2026). Flood zone maps complete the picture by showing where elevation work will be required before construction begins (Glynn County, 2026). Together those records turn a headline residual into a lot specific figure, which is the only figure an owner should negotiate from.
Recorded deeds then provide the market test. Deeds in the buyer entity name from actually closed purchases, checkable in county records, show what builders have truly paid for comparable island lots (Glynn County Clerk of Superior Court, 2026). If recent island deeds cluster near the residual, the method and the market agree. If they sit well below it, an owner should ask whether the specific lot carries a constraint the headline method missed. What an owner should not do is average island deeds with Brunswick deeds to reach a compromise number. Averaging across the causeway blends two different markets into a figure that describes neither, a mistake examined again in the context of whether larger lots in 31522 are worth more to builders than smaller lots.
Valuation tools make the same blending error automatically. Automated estimates draw on wide geographic sales pools that can pull mainland and island closings into one model (Zillow, 2026). For an island lot, that pooling systematically drags the estimate toward mainland levels. The error is not random. It runs in one direction, against the island owner, and it is a further reason to work from island deeds and the residual rather than from a screen figure.
What costs narrow the island premium in practice?
Insurance, flood compliance and carrying costs narrow the headline premium, and an honest comparison counts them. Island insurance, including wind and flood cover well above mainland levels, is a recurring charge on any island lot with a structure on it, and flood insurance pricing under current federal methodology reflects elevation and risk parcel by parcel (Federal Emergency Management Agency, 2026). During a long sale process those costs accumulate. Carrying costs over three to six months of market time run $15,000 to $35,000 on the research ledger for an island sale, covering mortgage or equity opportunity cost, insurance, taxes, utilities and maintenance (Frontier Capitals, 2026). A Brunswick lot held for the same period does not carry the same insurance burden, so the net gap between the two markets is smaller than the gross price gap, even though it remains large.
Selling costs narrow it further when the listed route is used. On a $550,000 island sale, commission typically runs 5 to 6 percent, or $27,500 to $33,000 (National Association of Realtors, 2025). Seller side closing costs add another 1 to 2 percent, and commissions plus closing costs together run 6 to 8 percent, or $33,000 to $44,000 on that example. Transfer taxes and prorations form part of that seller ledger on either side of the causeway. None of those charges creates the island premium, but each one takes a slice of it if the sale is handled through a full cost listing. An owner comparing a mainland framed cash offer with an island framed direct offer should compare nets, not headlines, on both sides.
The direct route on the island is designed to preserve more of the premium. Frontier Capitals operates as a wholesaler, purchasing from sellers itself and placing off market properties with builders. The sale stays entirely out of view, with no one touring the property, no open house events, no stretch of public advertising, and nothing filed publicly before ownership changes hands at transfer. Closing is flexible: 7 to 21 days when speed matters, or months out with a leaseback, against 60 to 120 plus days for a listed older island home. No commission is charged, saving the $27,500 to $33,000 documented above on the $550,000 example. Sellers pay no closing costs in that route, so the additional 1 to 2 percent disappears as well. No inspections or repairs are required, so the $10,000 to $25,000 repair credits routinely negotiated on older island inventory never arise. For an island owner, those savings are not a side benefit. They are the difference between realising the island premium and donating a large part of it to the sale process. Sellers who want to draw interest to a lot on those terms can review how St Simons Island homeowners attract cash buyers, keeping in mind that cash interest in an island lot should still be tested against the island residual, not against mainland cash offers.
When would a Brunswick comparison ever be useful?
A Brunswick comparison is useful only for questions that are genuinely about relocation or about the wider county market, never for pricing an island lot. If a family is deciding whether to sell on the island and buy on the mainland, comparing what the island lot will fetch with what a mainland house will cost is a legitimate household calculation. The island sale price in that calculation must still come from island evidence. The mainland purchase price comes from mainland evidence. Mixing the two evidence pools inside a single valuation is where the error enters.
Divorce and estate situations show the same distinction under pressure. Island pricing follows island logic, and a marital or estate home on the island must be priced from St Simons sales, not Brunswick mainland sales, because the island premium does not transfer across the causeway. That principle, documented in the island guides, protects both sides of a division: a spouse or heir who accepts a mainland framed value for an island property gives away value that the other party may later claim was mishandled. Where a probate property is involved, the cash route and its authority questions are covered in the report on whether a probate property can be sold for cash, and where a divorce sale proceeds without a courtroom fight, the process is covered in the report on selling during divorce without going to court. In each setting the valuation rule does not change. Island ground is priced from island sales.
There is also a limit to state plainly. The source material documents island finished prices, island residuals and island sample ratios in detail. It does not publish a verified Brunswick lot price, a Brunswick residual or a Brunswick builder demand rate. Any specific mainland dollar figure in a comparison would therefore be invented, and this report invents none. The comparison that can be defended is the one the material supports: island lots carry a large, scarcity driven premium over mainland lots, measurable on the island side through the residual method and recorded deeds, and not reducible to a tidy percentage drawn from data that does not exist.
Methodology and limitations
This report rests on the island sample of 17 older homes in 31522, 9 acquired by builders, on island new construction sales, and on county parcel, flood, permit and deed records for St Simons Island (Frontier Capitals, 2026; Redfin, 2026; Glynn County Board of Assessors, 2026; Glynn County Clerk of Superior Court, 2026). Area context draws on county and metro housing data for the combined market (U.S. Census Bureau, 2025). The figures are sample figures compiled for this report, not a census of the ZIP code, and the residual illustration is a simplified illustration, not a promise for any specific lot.
The central limitation is the one stated in the body: no verified Brunswick lot valuation is published in the source material for this set. The report therefore answers the comparison by method, documenting the island side with figures and establishing the direction and cause of the gap, rather than by presenting a paired dollar comparison the material cannot support. No mainland property was valued and no mainland appraisal was performed. An owner who needs a lot specific island figure should have the residual run against that parcel, including its flood zone, setbacks and tree constraints.
Conclusion
Residential lots on St Simons Island are worth far more than residential lots in Brunswick because finished island homes sell for $1.1M to $1.9M, island land cannot be expanded, and builders compete for the fixed stock of island parcels, leaving residuals near $550,000 to $650,000 in the worked illustration (Redfin, 2026; Frontier Capitals, 2026). Brunswick lots, on plentiful mainland ground a short drive away, are priced in a different market with different supply and a different buyer pool. The practical rule for any island owner is short: never price island ground from mainland evidence, and always test an offer against the island residual and recorded island deeds.
Owners who want an island lot valued on island evidence alone can telephone Frontier Capitals at 401-219-4207 or email [email protected].
If a buyer priced your island lot as if the causeway erased the island premium, what island sale would you show them to prove the premium is real?
Frequently Asked Questions
Is there a single percentage for how much more island lots are worth?
No verified paired percentage is published in the source material, and this report does not invent one. The island side is documented through finished prices of $1.1M to $1.9M and a residual near $550,000 to $650,000 in the illustration (Frontier Capitals, 2026; Redfin, 2026). The gap is large and structural, but its size varies lot by lot.
Why do Brunswick prices appear in island online estimates?
Automated tools pool sales across wide areas, so mainland closings can pull an island estimate down toward mainland levels (Zillow, 2026). Recorded island deeds are the correction. An owner should compare a lot against island builder purchases, not against a blended screen figure.
Does lot size change the comparison?
Yes, within the island market first. Larger island lots with workable buildable envelopes capture more of the scarcity premium, subject to flood setbacks and tree rules (Glynn County Board of Assessors, 2026; Glynn County Community Development, 2026). Size alone does not help if the envelope cannot support a valuable finished home.
Are island selling costs higher than mainland selling costs?
Commission percentages are similar, but island carrying costs run higher because wind and flood insurance sit well above mainland levels (Federal Emergency Management Agency, 2026). On the $550,000 example, commissions plus closing costs run $33,000 to $44,000 either way, while months of island insurance add materially to the holding bill (National Association of Realtors, 2025).
How quickly could an island lot sell directly?
A direct sale can close in 7 to 21 days once terms are agreed, with the seller choosing the date and a leaseback available (Frontier Capitals, 2026). A listed older island home, by contrast, commonly needs 60 to 120 plus days. Speed does not require accepting a mainland framed price.
Sellers in St Simons Island also ask How to Sell a House in St Simons Island in 14 Days?
Sources
- Frontier Capitals, 2026. 189 neighborhood builder acquisition sample: 17 homes sampled in 31522, 9 acquired by builders, average older home price 23.1 percent of new build. Market data.
- Redfin, 2026. Recently sold homes and new construction, ZIP code 31522, St. Simons Island GA. Market data.
- Glynn County Board of Assessors, 2026. Parcel records, flood zone designations, and lot dimensions for St Simons Island. Official record.
- Glynn County Clerk of Superior Court, 2026. Recorded deeds and plat records for 31522. Official record.
- Glynn County Community Development, 2026. Building permit and tree protection requirements for St Simons Island. Official record.
- Glynn County, 2026. Flood zone maps and permit records for St Simons Island. Official record.
- Federal Emergency Management Agency, 2026. National Flood Insurance Program: Risk Rating 2.0 methodology and elevation certificate requirements. Government data.
- National Association of Realtors, 2025. Highlights from the Profile of Home Buyers and Sellers. Industry report.
- Zillow, 2026. Home values and recently sold, 31522. Market data.
- U.S. Census Bureau, 2025. American Community Survey, housing characteristics for the Brunswick metropolitan area. Government data.