Thailand's eastern coastal strip runs from just east of Bangkok all the way down to the Cambodian frontier at Hat Lek. The area encompasses the coastal provinces of Chonburi, Rayong, Chanthaburi and Trat, and the further you go from Bangkok the better the beaches get.
The vast majority of budget travellers find themselves in this part of Thailand for one of three reasons: the island of Ko Samet, the Ko Chang archipelago off the coast of Trat, or the border crossing with Cambodia at Hat Lek/Koh Kong. All three of these are fine reasons to be in the area, but as is often the case, there's more to see and do than just that.
The beautiful beaches and islands have unfortunately attracted more than their fare share of short-sighted development projects. With virtually all of this region within a four to five hour drive of Bangkok, Eastern Thailand has borne the brunt of some of the biggest and most ill-conceived of Thailand's tourist-related development.
Pattaya, a once sleepy fishing village, was transformed into a heaving sun, sea and sex destination courtesy of it being used as an R&R destination for US troops during the American War. Development ran at a totally unsustainable rate, eventually only slowing down when Pattaya's beaches became so polluted that swimming became dangerous. The area has tried to clean up its act and re-package itself as a family destination; while environmental improvements have been made, Pattaya remains one of the sleaziest places in Southeast Asia. Thankfully, the seediness has not encompassed the nearby beach town of Bang Saen, and the fishing island of Ko Si Chang, both of which are worth a visit.
The next casualty was Ko Samet -- ostensibly a National Marine Park -- but you wouldn't know that upon setting foot on it (though you will be asked to pay the 200 baht entry fee). While the development has not had nearly the impact that Pattaya's did, there is nevertheless the typical blights that you can see anywhere in the world where a fast-buck takes precedence over a sustainable one. The island remains a good place to visit -- soft white sand beaches are but a bus and boat ride from Bangkok, making it a weekender's favourite. Just don't expect an unspoilt paradise.
Not far from Ko Samet, there's the very little-known Ko Mun Nork. Home to a single resort, if you're looking for no crowds and empty beaches, you could do a lot worse than here. Go on a weekday and you'll probably have the island to yourself.
After Pattaya and Samet the developers set their cranes on Ko Chang in Trat province. Thailand's third largest island (after Phuket and Ko Samui) caught Thai ex-PM Thaksin Shinawatra's eye, and large development projects have poured in despite the island's national park status. At least with its larger size and more rugged terrain, it can absorb a degree of development better than some of the smaller islands, but for only so long. A good site for more information on the development of Ko Chang is iamkohchang.com.
The Ko Chang Archipelago is comprised of about 50 islands, a handful of which have accommodation on them. If Ko Chang feels too mainstream, head to beautiful Ko Wai, family-friendly Ko Maak or -- perhaps one of Thailand's last island frontiers, magnificent Ko Kut.
After all of those beaches, don't forget to stop in Chanthaburi, an underrated province that was once part of French Indochina. It boasts some pleasant waterfalls, national parks and low-key beach towns, with the unsung provincial capital hosting a charming old town and eclectic heritage.