Communications in the Isle of Man were taken over by the GPO. The internal telegraph system was extended within a year to Castletown and Peel, however by then the previous lack of modern communications in Castletown had already started the Isle of Man Government on its move to Douglas. Due to increasing usage in the years following nationalisation, further cables between Port Cornaa and St Bees were laid in 1875 and 1885. By 1883 Smith's Directory listed several telegraph offices operated by the Post Office, in addition to those at Douglas, Ramsey, Castletown and Peel the telegraph was also available at Laxey, Ballaugh, and Port St.
Castletown, Dorset is found in the village, close to the entrance of Portland Port. The area still features several hotels and pubs, largely established for the navy personnel that once came from the port. The Osprey Leisure Centre is located in Castletown, which was formerly known as the Boscawen Centre, and was opened to the public in May 2007. Originally it was a private Royal Navy facility during the 1980s. Castletown also holds the Portland Community Hospital. This was originally a Royal Naval Hospital which served Portland's naval base from the late 19th century until 1957, when the hospital was handed over