Going from Guyana to Suriname is strange. The border station is enclosed by a huge security fence protecting the immigration office and ferry loading/unloading zone. You'll end up hanging out here for hours while everyone's papers are reviewed and processed (so inefficient!). Then you'll load up onto a ferry and cross the river to Suriname. Outside the security fence will be a dozen or so guys wanting to exchange your Guyana currency. You need to do this here because they won't take Guyana currency once you cross the river. It's one of the shadiest currency transactions I've ever done, and I fully expected to get scammed, but the Surinamese money I got turned out to be 100% genuine.