For those who will travel to Koh Samui by driving their own car, you can take a ferry at Donsak district.
There are 2 piers to choose from:

– Seatran Ferry Pier
– Raja Ferry Pier

To bring your car onto the ferry to Koh Samui, it is recommended to book a ferry in advance, at least 4 hours. You can book online via the website or via Line Add.
For Seatran Ferry, you can book at any 7/11 counter service branch.
I have posted the links for each pier for you.
https://www.seatranferry.com/
https://www.rajaferryport.com/

As for passengers, it is not necessary to book in advance. You can buy tickets at the pier.
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