Cosham is about Portsmouth-average for crime. The recorded rate works out at roughly 136 incidents per thousand residents over the last twelve months. That sits about 8% above the wider Portsmouth area figure. Just under 2,000 reported incidents across the year, in a population of around 14,400. No outlier in either direction.
Across the twelve months to March 2026, the area recorded around 1,960 incidents. Spread across a population of roughly 14,400, that gives a rate of about 136 per thousand residents. The wider Portsmouth area average for the same period sits closer to 126 per thousand, so Cosham runs about 8% above the local-authority figure. That gap is small in statistical terms, which is why the rating ends up at average rather than worse-than-average. Cosham sits in the same band as most of mainland Portsmouth's neighbourhoods, neither registering as a hotspot nor reading as unusually quiet.
The geography accounts for most of that figure. Cosham contains the bus interchange, the railway station, the High Street, and the main mainland artery into and out of Portsmouth, all packed into a small footprint. Town centres that double as transport hubs always pull more reported crime into the catchment than purely residential streets do, because they carry more footfall, more retail, more night-time activity, and more people passing through who do not live there. The same incident on a quiet residential road in a separate postcode gets coded to that postcode; the one near the bus station gets coded to Cosham. The headline reflects the mix rather than what life on any one specific street looks like.
Recorded crime covers everything from a stolen bike outside a shop to antisocial-behaviour call-outs around closing time to the much rarer serious incidents. The headline rate compresses all of that into a single number, which is why a street-level check matters more than the area average for any specific buyer. A flat above the High Street will see a different daily texture from a house on one of the quieter residential streets toward Highbury or Old Wymering, even when both share the postcode and the headline figure.
For context, a recorded crime rate near the local-authority average is what most southern English urban areas look like when you measure them honestly. It runs higher than a rural Hampshire village and lower than the busiest pockets of the inner city. Cosham's history of serious disturbance, for what it is worth, peaks at King Cnut's invasion of the south coast in 1015, while King Æthelred the Unready lay terminally ill in the village. Nothing in the last year's 1,960 incidents comes anywhere near that.
Average is the honest verdict. Safer than the noisiest stretches of central Portsmouth, busier than the quiet residential streets at the back of the area, and not the dimension that should drive the buying decision either way.