*this list will likely grow as user adoption grows. If you are aware of any exchanges, that list SWT, that are missing here contact us to add it to the list.
Bittrex: SWT/BTC pairing offered
HitBTC: SWT/BTC and SWT/ETH pairing offered
YoBIt: SWT/BTC and SWT/USD
*90% of SWT trades happen on Bittrex
Another way to get SWT is to connect privately with a peer to exchange SWT by sending/receiving it to any public ERC-20 token address, in exchange for whatever the parties offer. Some people use https://localbitcoins.com/ to connect with other locals. Do your due diligence, this service operates much like a craigslist site and is not regulated.