Cosham is where Portsmouth runs out of island. A high street, a junction, and a hill behind it. Three railway routes to London and a Greggs. It's the pinch point the rest of the city has to drive through, dressed as a 1930s semi with a driveway.
The housing stock is the giveaway. Just over half the homes are houses, getting on for four in ten are flats, and roughly two in a hundred are bungalows. The dominant age band is the post-war run from 1950 to 1982, with another big slug from the 1930s and 1940s, which between them account for the look of nearly every street. Pre-1930 stock is only about one in ten homes. The energy ratings tell the same story: about half the homes sit in bands A to C, around four in ten are band D, and roughly one in eight is band E or worse. This is not Victorian Southsea with its draughty terraces, and it is not new-build Drayton with its underfloor heating. It is the bit in between, which is most of the country.
A typical sale over the last year went for around £304,000, off the back of 134 transactions. That's enough volume to mean the comparables are actual comparables rather than estate-agent guesswork. The split by type does the rest of the talking. A flat goes for about £155,000, a terrace around £314,000, a semi about £328,000, and the rarer detached lands near £575,000. Council tax distribution leans cheap: the modal band is C, and getting on for half the dwellings sit in bands A or B, which is what happens when you fold Paulsgrove and Wymering into the figures.
The typical private rent across the Portsmouth area runs at about £1,360 a month, with annual change of around three per cent. That's a city-wide figure rather than Cosham's own, but the local lettings sit inside that envelope.
Crime in Cosham runs at about 136 incidents per thousand residents over the last year, which is roughly eight per cent above the Portsmouth average. That puts it at the average end rather than meaningfully above or below. The bus interchange and the high street do the heavy lifting on the stats, which is what happens anywhere a town centre does double duty as a transport hub.
The schools picture is the weakest of the dimensions. Across the wider catchment, twenty of the forty-nine graded inspections come back at good or better, with two rated outstanding, one requires improvement and one inadequate. That's around four in ten at good or better, which is below where you'd want to be. Key Stage 2 maths scores at the seven primaries in the wider district sit just above the expected standard, and the one secondary in the district lands around 36 on the Attainment 8 score, which is below the national average. Buyers who care about catchment do their homework street by street rather than trusting the postcode.
Cosham is well-served for getting out of itself. The town centre is around eight minutes by car, eleven by foot. Cosham Rail Station sits at the foot of the high street and offers three separate routes to London, plus services west toward Southampton and Cardiff. Hilsea Rail Station, Portchester Rail Station and Bedhampton Rail Station are all within the wider footprint, and Fratton, Portsmouth and Southsea and Portsmouth Harbour stations sit further south on the island. Only around two in a hundred residents actually commute by train, mind. About 46 per cent drive, 16 per cent walk, and about a fifth work from home. There are 114 bus stops inside the area, which is a lot for somewhere this size and reflects Cosham's role as the gateway interchange. Broadband is the strong card: gigabit availability sits at around 91 per cent of premises, with full-fibre at the same level, and no premises below the universal service obligation. The car-free option works here in a way it doesn't in most of Portsmouth's mainland fringe.
The flood picture is mostly fine for the residential streets. About six per cent of postcodes carry a high flood risk and nine per cent a medium one, with the rest at low or negligible. The Environment Agency's climate-adjusted flood zone covers around half the area on paper, but the actual present-day risk is concentrated in a small band. Greenspace access is the standout: the average distance to greenspace is around 180 metres, with about 25 separate greenspaces within a kilometre of a typical postcode. Blue space sits about 660 metres away on average. This is the dimension Cosham scores top marks on, and it earns them.
Heritage constraints are light. There are 26 listed buildings in the area, three of them grade II star and the rest grade II, plus two conservation areas at Old Wymering and Hilsea Lines and two scheduled monuments. Most of Cosham sits outside those boundaries, which means most owners can change their windows without writing to a planning officer. Inside the Old Wymering conservation area or near the listed stock, the rules tighten, but that affects a small fraction of the housing.
Around six in ten households own their home, which is a normal ratio for an outer suburb of a southern city. The median age is around 39, the median household income lands at around £58,500, and household sizes are mixed: a quarter of households are single-person, around a fifth are couples with children, and about one in seven is a lone parent. This is not a transient renter postcode and it is not a retirement enclave. It is working families paying mortgages.
This page also covers Paulsgrove on the western flank and Wymering between the two, both of which sit inside the Cosham ward and pull the council-tax distribution toward band A.
This suits a buyer who wants the Portsmouth postcode and the cheaper end of the family-house market, who is happy to drive seven minutes to a Tesco and twelve to the city centre, and who values being two minutes from a station that goes to London three ways.
This does not suit the buyer who needs a top-quartile primary on the doorstep, the buyer who wants Portchester's quieter conservation-area pretensions, or the buyer who turned up in Cosham because Paulsgrove was a step too far. There is a postcode for that, and it costs more.
Cosham is above average, on balance, and the surrounding area and green-space access are why. The schools are the weak card. Cheaper than Drayton, drier than Southsea, less raw than Paulsgrove. Cosham is the compromise that works.