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ABS 2021 Census · Updated 21 May 2026
Semaphore is a well-established middle-ring suburb of Adelaide, Australia, with a population of approximately 2,749, making it a boutique locality. Located approximately 15 km from the Adelaide CBD, Semaphore is a middle ring area in South Australia. The median household income is $89,336 per year.
Moderate income levels in Semaphore indicate steady rental demand from working households. Its proximity to the CBD adds a strong location premium.
Official Australia Post postcode for Semaphore. A postcode may cover multiple suburbs.
Australia Post Postcode Finder →Usual resident population at the most recent census.
Weekly median rent for occupied homes. Live rental data integration coming soon.
Annual median household income (before tax) across all households.
Straight-line distance from the suburb centroid to the nearest capital city CBD. Actual driving distance will be longer.
Estimated 1 school within or near this suburb.
Find schools near Semaphore on My School →Estimated 1 park and green spaces near this suburb.
Monthly median mortgage repayment for households currently paying off a mortgage.
Proportion of separate houses versus units, townhouses, and other home types. Useful for investors assessing rental demand mix.
Semaphore is a smaller community of 2,749 — about 74% of the South Australia suburb median (3,699) — so investors should factor in the narrower buyer pool and longer average time-on-market. Households here earn $89,336/year on average — 10% above the SA suburb median of $80,964 — a modest premium that supports resilient owner-occupier demand. Rent of $320/week (80% coverage of the $1,733/month median mortgage) leaves a gap of roughly $346/month that a typical investor bridges with negative gearing, depreciation and capital growth. 15 km from Adelaide places Semaphore in the middle commuter belt, close enough for daily trips by car or rail but at a materially lower price point than inner suburbs.
Middle-ring locations like this one historically reward patient holders — focus on homes near catchment-zone schools and major transport. Local rents consume roughly 19% of household income — a useful sanity check on tenant affordability.
How Semaphore stacks up against the median of all South Australia suburbs in our dataset. Positive values mean Semaphore sits above the state median; negative means below.
| Metric | Semaphore | SA median | Δ vs state |
|---|---|---|---|
| Population | 2,749 | 3,699 | -26% |
| Median household income | $89,336/yr | $80,964/yr | +10% |
| Median rent (weekly) | $320 | $320 | 0% |
| Median mortgage (monthly) | $1,733 | $1,616 | +7% |
| Distance to CBD | 15 km | 13 km | +15% |
| Separate houses | 59% | 73% | -14pp |
Pre-inspection briefing for Semaphore — every item is derived from public datasets, with full citations in our data sources page.
Limited buy-and-hold upside: a small population of 2,749 means liquidity is thin and capital growth tends to lag the wider South Australia market over full cycles.
Moderate rental coverage: rent of $320/week covers 80% of a $1,733/month mortgage, leaving a $346/month gap that an investor bridges with equity, depreciation and tax benefits.
Only 59% of dwellings are separate houses (vs 73% SA median) — this is a unit and townhouse market, where cosmetic flips struggle against body-corporate restrictions, thinner after-reno uplift and competing new supply.
Run the numbers on a Semaphore property
Scenario comparison, cash flow analysis, tax modelling, and PDF export — all in one place.
Create free account →Capital-growth expectations for Semaphore are modest for 2026 — incomes 10% above the SA median of $80,964 and a population of 2,749 suggest gains will lag headline metro markets. Rental coverage runs at ~80% of the typical mortgage ($1,387/month rent vs $1,733/month repayment), keeping cash flow in positive or near-neutral territory. The EquitySight investment score of 61/100 places Semaphore in the upper-middle tier of Australian suburbs we profile, and overall investor sentiment is balanced heading into the second half of 2026.
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Semaphore scores 61/100 on our EquitySight investment framework — a good rating. That score is driven by a population of 2,749, median household income of $89,336/year and median weekly rent of $320. Whether it fits your portfolio depends on whether you are targeting cash flow, capital growth, or a value-add renovation — all three are scored with suburb-specific numbers elsewhere on this page.
The main demand drivers in Semaphore are proximity to Adelaide (15 km), an above-state-median household income of $89,336/year, a dwelling mix that is 59% separate houses, roughly 1 schools and 1 parks within the catchment. Together these shape both owner-occupier and tenant demand and are the factors we weight most heavily in the suburb's investment score.
Semaphore has a usual resident population of approximately 2,749, compared with a South Australia suburb median of 3,699 — placing it in the lower half of the state's suburbs by size. Population is the clearest proxy for market depth: more residents mean more transactions and typically a shorter average days-on-market on resale.
Semaphore sits 15 km straight-line from the Adelaide CBD. This is comfortable commuter territory, with reasonable rail and road access to the city.
The most recent census recorded a median weekly rent of $320 in Semaphore, equating to approximately $16,640/year in gross rental income (state median $320/week). Market rents have typically drifted above the recorded figure — verify against current listings on realestate.com.au and Domain before making an offer.
The median monthly mortgage repayment in Semaphore is $1,733, or approximately $20,796/year (vs $1,616/month state median). Stress-test your own borrowing at rates 1–2 percentage points above today's to make sure you can still service the loan through an RBA tightening cycle.
A median weekly rent of $320 works out to $1,387/month, covering 80% of the median mortgage repayment of $1,733/month. That leaves a $346/month shortfall (around $4,152/year before tax benefits), so a typical owner-occupier-priced property here is negatively geared. Actual cash flow depends on your deposit, loan terms, ownership costs and marginal tax rate — run the full numbers in our rental yield calculator.
The main risks are a thin buyer pool (2,749 residents), interest-rate sensitivity on the $1,733 median mortgage, the broader South Australia market cycle. Each of these is covered in the Risk Factors section above with suburb-specific numbers rather than generic warnings.
Every number on this page comes from the ABS 2021 Census of Population and Housing, Australia Post postcode reference data, and OpenStreetMap amenity tiles. The investment score, strategy verdicts, and comparison table are computed deterministically from those inputs — no opinion, no estimation. See our full methodology and the data sources and licences for the formulas we use.