You can reach to the Ho chi Minh city located in this country by taking numerous direct flight from India. From their you can get a domestic flight which would drop you off in the Nha Trang region. Flights such as Bangkok Airways and Air India would serve you to the Ho chi Minh destination.
You can take a local flight from Ho Chi Minh city to the Cam Ranh Domestic Airport. From there you can reach this location with the help of cabs or taxis.
You can always rent a car or a taxi for reaching this place, however that might be a bit costly for you compared to the other means of transportation.
There is a local railway connectivity and you can get a train from the city of Hanoi. The railway station is located near to the cathedral and you can easily get yourself
There are numerous buses which would enter this area from the Ho Chi Minh city. You can easily reach this destination by either public or private transportation in around 5 hours.
No known methods of travelling to this bay by sea are known.
You can move around this location by taking any public bus or motorbikes. In case you want a bit of privacy then there are options such as taxis and cabs to consider.