This large natural area about fifty kilometers east of Rayong city is part of the Botanical Gardens Organization which has several projects to preserve unique natural places across Thailand. The others are at
Chiang Mai, Khon Kaen, Phitsanulok, Sukhothai and Phang Nga.
The Rayong Botanical Garden contains vast swamps covering 3,800 square meters that you can explore by boat or kayak (to rent on-site) to discover its flora and fauna, especially its birds, and a forest sometimes like a virgin forest in which it is very pleasant to ride a bicycle (there are mountain bikes for rent).
More than its classic botanical garden side with the cultivation of plants which for some cannot grow elsewhere, it is the exceptional natural setting of the garden that it offers which makes it one of the must-visit places in Rayong province. Allow at least 1 hour to visit the place to cycle around or take a boat tour and 2 hours to do both. Note, that the place is quite popular and croded with locals on weekends.