The mainland departure-point for Ko Samet is the tiny fishing port of Ban Phe, about 200km form Bangkok. There are hourly direct buses from Bangkok’s Eastern Bus Terminal (Ekamai) to Ban Phe pier, departing between 5.30am and 5.30pm., but if you miss those you can easily take one of the more frequent buses to Rayong and then change onto songthaews (small minibuses), which leave Rayong bus station about every thirty minutes and take half an hour to reach Ban Phe pier. Alternatively, you could take one of the tourist minibuses from Thanon Khao San to Ban Phe. From Pattaya, there are hardly any direct Ban Phe Buses so you’re probably best off taking a bus to Rayong and then one of the half-hourly songthaews. There are tourist minibuses from Pattaya as well, which can be booked through most hotels. So if you want to go to one of the other beach, wait and buy your boat ticket at Ban Phe. Coming by bus from points further east, such as Chanthaburi or Trat for example, you’ll most likely be dropped at the Ban Phe junction on Highway 3, from where a songthaew or motorbike taxi will take you the remaining 5 km to the pier.

Once in Ban Phe, you need to decide which beach you want and then choose your boat accordingly. Some boats are owned by individual resorts and ferry both per-paid package tourists and fare-paying independent travelers; others make the crossing as soon as they have enough passengers (minimum eighteen people) or sufficient cargo to make it worth their while. So the best way to get on the boat with the most people and buy your ticket on board rather than from one of the boat-specific booths on the pier-head. All boats charge the same fares.

The easiest place to get to on Ko Samet is Na Dan pier on the northeastern tip of the island, which is the most convenient arrival point for the beaches of Hat Sai Kaew, Ao Hin Kok, Ao Phai, Ao Tub Tim and Ao Nuan, an quite feasible for all the other beaches as well; songthaews meet the boats at Na Dan and will take you as far as Wong Duan, or you can walk to your chosen beach. Boats to Na Dan leave from Ban Phe’s Saphaan Nuan Tip pier, they take about thirty minutes to get to Samet.

There are equally frequent boats to Al Wong Duan, which is also convenient for the nearby beaches of Ao Cho and Ao Thian. Some boats go to Wong Duan direct form Ban Phe’s Saphaan Nuan Tip pier, others stop at Na Dan first – it’s often a question of haw many people there are. Some of the bungalow resorts on the smaller beaches also run boats from Ban Phe direct to their beach. Get to Ao Phrao at different pier, called Saphaan Sri Ban Phe pier.
Reference info. from The Rough Guide