Three “dolphins” have been spotted swimming in the River Thames.

Photographer Jason Arthur was able to capture one on camera as it popped its head above the water near Gravesend Town Pier.

He told KentOnline there were around three in the river at about 2.30pm this afternoon (June 9) and are thought to have been there for a few days.

It is not known if they were in fact dolphins or porpoises - both of which have previously been seen splashing around in the water near Gravesend and Northfleet.

The two species are often mistaken for one another, however, there are a few differences in their faces, fins and body shapes.

Dolphins have longer snouts, bigger mouths, more curved fins and are longer and leaner than porpoises.

In February, RNLI crews first thought they have seen a gam of porpoises swimming towards their lifeboat in the River Thames, near Northfleet.

However, it was in fact a pod of dolphins.

Elsewhere in the county, the aquatic creatures have been caught playing in the River Medway, in the sea near the Folkestone Harbour Arm and near Sheerness.

Common dolphins can be found in waters all around the UK, but are more common to the southern and western coastal areas.