| Cable & Wireless | ||
| Cable rates | Colonies & Australia | 1872 - 1953+ |
| Cable ships | Australia/New Zealand Pacific & Indian oceans |
Cable ships with duties related to laying and repairing cables in, to and within Australia. |
| Cable subsidies | Colonial | |
| Camels | Western Australia | 300 camels at Dioroite King en route to Coolgardie. |
| Card | Australia | Non-attendance actions with 1948 form. |
| Censorship | Australia | Introduction at the beginning of World War 2. |
| Australia | Use of "Passed by Censor" hand stamp on telegrams. | |
| Chess | South Australia | Game played over the telegraph lines. |
| Game between Narridy and Clare Chess Clubs in 1880. | ||
| Chifley, Ben | Australia | 1947 telegram from Chifley. |
| Children's books | May Gibbs | Childhood home at Harvey, WA. |
| Coastal Radio Stations | AWA/PMG | |
| Coat of Arms | Australia | 1908 and 1912 designs and their meaning. |
| Coat of Arms design on stamps for payment of charges. | ||
| Cobb & Co. | Queensland | Stage coach at Eulo, |
| South Australia | Suspicious dealings with the SA Government. | |
| Cockatoos | Western Australia | Damage to lines near Marble Bar. |
| Coles, G. J. (retailer) | Victoria | St James was the birthplace. |
| Collar stamps | Advertising services of a company. | |
| Collect telegrams | Australia | Concept, regulations and forms. |
| Correction to a message | Australia - AWA | Correction notice issued for a Beam message. |
| Australia - OTC | Correction notice issued for an OTC message. | |
| Cracknell, E. C. | NSW | Superintendent of Telegraphs (1858 - 1893). |
| Cracknell, W. J. | Queensland | Superintendent of Telegraphs. |
| Cricket | South Australia | Adelaide Oval date stamp. |
| Victoria | Cricket Ground, MCG date stamp | |
| Bill Johnston | Telegrams for his Test Debut and selection into the 1948 Ashes team to England. | |
| Ray Lindwall | Telegrams for his record breaking achievement (1959). | |
| Stan McCabe | Message sent from Richmond City to London in 1938. | |
| Reuters | Cricket news sent from the MCG to London. | |
| South Australia | Broadcasting by telegraph. | |
| Crocodiles | Queensland | An obstacle in getting to school. |
| Currency | Australia | Conversions between pounds (£) and dollars ($) |
| Curtin, John | Australia | 1940 Telegram from Curtin to his wife for her 50th birthday. |