Pentwyn
vs Pontprennau and Old St Mellons
Pontprennau and Old St Mellons has the younger population: 19% of residents are aged 15–29, against 19% in Pentwyn. Homes in Pontprennau and Old St Mellons sold for a median of £299,995, 43% above Pentwyn. Pentwyn has more green space nearby (29% within 500 m, against 27%).
People
Pentwyn has 16,197 residents in 6,516 households; Pontprennau and Old St Mellons has 11,713 in 4,910. Pentwyn has the higher share of residents aged 65 and over: 16%, 4.4 percentage points more than Pontprennau and Old St Mellons (Cardiff: 15%). Pentwyn has the higher share of people living alone: 30%, 3.1 percentage points more than Pontprennau and Old St Mellons (Cardiff: 32%).
Homes and prices
The most common type of home is terraced houses in Pentwyn (46%) and detached houses in Pontprennau and Old St Mellons (44%). Pontprennau and Old St Mellons has the higher share of owner-occupied homes: 71%, 12.3 percentage points more than Pentwyn (Cardiff: 58%). Pontprennau and Old St Mellons has the higher share of private renting: 18%, 1.1 percentage points more than Pentwyn (Cardiff: 24%). Over two years, homes sold for a median of £210,000 in Pentwyn and £299,995 in Pontprennau and Old St Mellons, against £270,000 across Cardiff.
Surroundings
Pentwyn has the higher share of land within 500 m that is green space: 29%, 2.2 percentage points more than Pontprennau and Old St Mellons (Cardiff: 19%). A typical postcode has 75 everyday shops and services within a 15-minute walk in Pentwyn, and 48 in Pontprennau and Old St Mellons. The typical postcode is 242 m from the nearest school in Pentwyn and 570 m in Pontprennau and Old St Mellons. The typical postcode is 2,198 m from the nearest tram stop or railway station in Pentwyn and 3,484 m in Pontprennau and Old St Mellons. Gigabit-capable broadband reaches 92% of premises in Pentwyn and 91% in Pontprennau and Old St Mellons.
Safety
Over 12 months, police recorded 76 crimes and incidents per 1,000 residents in Pentwyn and 66 in Pontprennau and Old St Mellons, against 118 across Cardiff. Police.uk records crimes by approximate location, not by where victims or offenders live. Busy streets, shops, stations and nightlife record more. Figures are counts, not a measure of personal risk.
Sources: Census 2021 (ONS) · HM Land Registry Price Paid Data · official school registers · © OpenStreetMap contributors · Environment Agency · data.police.uk, 12 months to Aug 2026 · Ofcom Connected Nations
In brief.
Each ward in a few lines, from its own page.
Pentwyn is one of 28 wards in Cardiff, home to 16,197 people in 6,516 households (Census 2021). Homes sold for a median of £210,000 over the past two years, 22% below the Cardiff median. On average 29% of the land within 500 metres of a home postcode is green space — 57% above the Cardiff average.
Pontprennau and Old St Mellons is one of 28 wards in Cardiff, home to 11,713 people in 4,910 households (Census 2021). Homes sold for a median of £299,995 over the past two years, 11% above the Cardiff median. On average 27% of the land within 500 metres of a home postcode is green space — 45% above the Cardiff average.
More comparisons.
Pentwyn and Pontprennau and Old St Mellons next to other wards of Cardiff.