As the island has slow style, internet do the same Anyway the mobile coverage and internet are available but not everywhere in the island and as we told, the data transfer can be slow. Maybe is your opportunity to leave the mobile phone at home !!! You can buy a Metfone Sim card before to reach Sanloem Island that is very cheap and you cn have internet data and have betetr signal if you can’t live without your mobile phone! High speed internet are provided only at luxury resorts.
At now there aren’t ATM or banks as on the largest island Koh Rong. Also credit cards are not allowed so before to reach the island you must provide to withdraw cash on the mailand in Sihanoukville or where you are.
In the island you will not have electricity always during the day and the night, but only few hours per day as the electricity comes from generators and solar panels power.
Being Koh Rong Samloem an half desert island, so still undeveloped, you must consider that in the island or better into the jungle there are some inhabitants as monkeys, snakes, spiders, dogs, giant geckos and hornbills. So take care and for example if you want do trekking inside the jungle is recommended go before the sunset and is recommended bit with feet or with a stick during walking so snakes can go away from your path.
Anyway being an half desert island there are sand flies, there are on sand but you’ll not see them. Is common that can bit you, leave marks and cause irritation, so is recommended a strong repellant.
During peak season from December to March you absolute must book in advance your bungalow because it’s the most visited period.