I rather swim indoors in a pool because then I know beforehand how warm the water is etc. Swimming outdoors is always... I dunno...
In Finland we are happy if we are able to get 19 or 20 Celsius degrees in lakes in summers, usually it is below that. It is bearable but a bit chilly to my taste. Sea water is always several degrees colder.
However, when the weather is warm-ish (like around 25 C or warmer), we start getting constant warnings that due to warmer weather the lakes (and possibly sea) are now full of the toxic "blue-green algae" so swimming should be avoided. Oh great, the few weeks when it would be warm enough to swim, the lakes become toxic and shit...
Then again, my experiences in the warm Thailand aren't much better.
- In one tourist resort, sure the sea water was nicely warm (I figure 28 C or so), but it was dirty as heck. A big plastic rice sack was floating by me (I picked it up and brought it to the beach) and there were other smaller (plastic) garbage there too. When I got out of the water, I felt itchy, the water was probably quite polluted as the waste go directly to the sea I believe.
- In another beach by the sea which wasn't quite as popular (and polluted), I saw lots of stranded jellyfish on the beach in the morning. The heck I am going to swim among jellyfish, no thanks! There were also some other... things... on the beach I don't quite recognize, possibly related to some kind of snakes in the water? I was not going to find out. If I recall right, the beach was called "Chao Lao beach".
- There was a big lake in one place near the Cambodian border. The water was not clear, more like muddy. Anyway, when I saw a local dog poo into the water, I decided not to swim in it. (Actually it pooed on a small pier and the dog owner kicked the piece of poo to the lake).
There was one (or two, I think they were quite near to each other) waterfalls in Thailand which were very nice to swim in. I don't recall their names but I have the places in my GPS phone. The water was crystal clear because the water was changing all the time (more water kept coming from the small waterfall), and there were big fish in the tiny pond there who were not afraid at all of e.g. human, as they apparently didn't have any natural enemies in the same pond. It was kinda magical to slowly swim and dive through the flock of big fish which didn't care about you much. The water was nicely warm, I'd say maybe 26 C even though more colder water kept coming from the mountains to the pond.
These waterfalls seemed to be mainly used by the locals, I think only once I spot another "farang" there.
Post edited July 08, 2018 by timppu