Hat Lek (also spelt Haad Lek, Had Lek, Hadlek, Hatlek) is the location of the southern-most border crossing between Thailand and Cambodia. Its Cambodian counterpart is Cham Yeam, about 8km from Koh Kong.
Hat Lek is the name of the border. The only things here are a few shacks selling drinks and possibly a guesthouse. If you're desperate for a break from border hassles, head 15km further to Ban Khlong Yai, which has nice seafood but no beach.
The nearest decently connected Thai town is Trat 60 km away; Chantaburi, a major hub, is a further 50km (1 hour) from Trat. From Trat, minibuses to the border depart every 45 minutes between 06:00 and 18:00, taking between 1.5 and 2 hours, 120 baht. A cheaper and more breezy option involves songthaews (pickup trucks that act as local buses). First take one from Trat to Ban Khlong Yai (80 baht); then catch another one the remaining 15 km to the border (20 baht).
Watch out for overpriced transport scams at the border if entering from Cambodia. Transfers costing 1400 baht have been threateningly forced upon some unfortunate travelers. If someone prevents you from taking either a minibus or songthaew, walk away. If they persist, head away from the immediate border area, head up the hill for about 150m to the police checkpoint and then pick up a songthaew or minibus from there.
Buses serving Trat depart from either the Eastern Bus Terminal (Ekamai) or the Northern Bus Terminal (Moh Chit). Daytime direct 1st class buses from Ekamai(~240B) average a bit more than 5 hours, while the less frequent services from Moh Chit take a little less; late-night services are quicker still. While most 2nd class buses(188B, air-con) take a bit longer as they may make more stops and use slower and less direct routes. The midnight departure from Ekamai takes only 4.5 hours.
Head across the border to Koh Kong, 8km away. The border opens at 07:00 and closes at 20:00. The ferry to Sihanoukville from Koh Kong no longer runs. Onward travel from Koh Kong to Sihanoukville and Phnom Penh is by full size air conditioned bus which leaves from Street 3 at around 08.00 daily.
(NB!! The Dugout Hotel is not in Hat Lek but in Koh Kong in Cambodia, this is a wrong entry!!!)