According to the last major Census of India (2011), Kadmat has a population of approximately 5,404 residents. The demographic growth rate has traditionally been steady, though constrained by the island's limited land mass and resources. The gender ratio is relatively balanced.
The population is almost entirely composed of ethnic Malayalis who follow Islam (predominantly the Sunni sect and the Shafi'i school of law). The indigenous population is classified as a Scheduled Tribe (ST) under the Indian Constitution due to their unique geographical and cultural isolation.
The primary language spoken is Malayalam, though the local dialect, known as Jeseri (or Dweep Bhasha), is heavily influenced by Arabic and old Malayalam. English is widely taught in schools and understood by the younger generation and those working in tourism. The literacy rate on Kadmat is notably high—well over 85%—reflecting the UT administration's strong focus on primary and secondary education.