Indians have to take a flight to Bangkok, and then take the Nok Air or Air Asia to Trang. All the major cities of India like Mumbai, Delhi, Chennai, Ahemdabad are well connected to Bangkok via the popular airlines like Thai Airways, Indigo, Jet Airways, Air Asia.
You can take a flight from your respective country to Bangkok, and then there are 2 daily flights operating from Bangkok to Trang by Nok Air and Air Asia. These take 60-90 minutes.
There are public vans that depart for Trang from neighbouring provinces.
There are two daily trains operating from Bangkok to Trang taking around 15 hours, making it a rough journey.
Buses depart daily from Bangkok to Trang, which is a 12 hour journey. Buses from Satun and Krabi depart for Trang too.