River Island – Portsmouth – Opening Hours & Store Details River Island, which occupies a convenient site in Cascades Shopping Centre, is located on Unit 154 Commercial Road, approximately a 1.31 mile driving distance south of the centre of Portsmouth (a few minutes walk from Portsmouth & Southsea Station). The clothing store is perfectly located to serve people from the locales of Portsmouth City Centre, Old Portsmouth, Fratton, Somers Town, Gosport, Milton, Southsea and Portsea. Here you’ll find the specifics for River Island Portsmouth, including the business times, address particulars, telephone number and other important information.