Hong Kong, with a land area of only 1,099 square kilometres has a population of more than six million. Every day, over 11 million passenger journeys are made on a public transport system which includes two high capacity railways, trams, buses, minibuses, taxis and ferries.
Hong Hong is one of the very few places in the world where public transport does not rely on public subsidies. The high density of population and the control of the real estate linked to transport are certainly the reasons behind this fact. This favourable financial situation allows to permanently invest in the infrastructures making the overall transport situation looking better and better.
The fare collection system uses contactless cards, credit card size magnetic tickets and fare boxes. Progressively, the magnetic tickets should be abandoned for the contactless cards. Like in London with Oyster, the Octopus card in Hong Kong is a store value card from which value is deducted as you travel. When you are in closed areas like underground, the fare is distanced based but as soon as you board vehicles, it is a flat fare which becomes variable if you go to suburbs. It is easy, cheap and convenient to travel on the Hong Kong public transport and I never felt unsecured. It is difficult to verify fares paid on the go but fares being low, I believe you don't worry so much. If you really want to know, just go on one of these display machine to get instant display of your recent trips.

Below are a number of useful links to learn everything about the Hong Kong public transport.