Port Blair mean time was the time zone of the Andaman and Nicobar Islands of India in the Bay of Bengal. The time zone was set up during the early 19th century and has been described as 17 minutes and 17 seconds (UTC+6:10:37) ahead of Calcutta Time (UTC+5:53:20). It remained in effect until 1 January 1906 when Indian Standard Time became the official time of India.

• "Note on the earthquake of 31 December 1881, Records of the Geological Survey of India,, XVII(2), 47-53, 1884". Cooperative Institute for Research in Environmental Sciences (CIRES). Retrieved 13 August 2006.