Offshore casino sites are casino sites that don't genuinely operate in the same jurisdiction in which they offer their services. Most countries require online casinos to have a local license to operate, and they must comply with a set of rules to get one. If a site doesn't want to do that, it can operate in a country with laxer restrictions. Consequently, playing on these offshore sites is a lot riskier but sometimes the only option if online gambling is not tolerated where you live.